Cellulose and hemicelluloses are the most prevalent sources of carbon in nature. Currently many approaches employ micro-organisms and their enzyme products to degrade plant feedstocks for production of bioenergy. Scar...Cellulose and hemicelluloses are the most prevalent sources of carbon in nature. Currently many approaches employ micro-organisms and their enzyme products to degrade plant feedstocks for production of bioenergy. Scarab larvae are one such model. They consume celluloses from a variety of sources including plant roots, soil organic matter and decaying wood, and are able to extract nutrients and energy from these sources. In this paper, we review the physicochemical properties of the scarab larval gut, the diversity and digestive role that microflora play in the scarab gut and discuss the potential for applying these digestive processes in bioreactors for improving bio-fuel production. Scarab larvae are characterised by their highly alkaline midgut which is dominated by serine proteinase enzymes, and a modified hindgut which harbors the majority of the intestinal microbiota under anaerobic conditions. Evidence suggests that digestion of recalcitrant organic matter in scarab larvae likely results from a combination of endogenous gut proteinases and cellulolytic enzymes produced by symbiotic micro-organisms. Most of the easily digestible proteins are mobilized and absorbed in the midgut by endogenous proteinases. The hindgut contents of scarab larvae are characterized by high concentrations of volatile fatty acids, the presence of fermenting bacteria, and typical anaerobic activities, such as methanogenesis. The hindgut typically contains a wide diversity of micro-organisms, some of which appear to be obligate symbionts with cellulolytic potential. As a result, the scarab larval gut can be regarded as a small bioreactor resembling the rumen of sheep or cattle, where solid food particles composed of cellulose, hemicellulose, pectin and polysaccharides are degraded through enzymatic and fermentation processes. Together these observations suggest scarab larvae have potential to assist the bio-fuel industry by providing new sources of （hemi）cellulolytic bacteria and bacterial （hemi）cellulolytic enzymes.展开更多
The objective of this study was to evaluate the effects of adding formic acid and corn flour supplementation to banana pseudostem silages on the nutritional quality of these silages,growth,digestion,rumen fermentation...The objective of this study was to evaluate the effects of adding formic acid and corn flour supplementation to banana pseudostem silages on the nutritional quality of these silages,growth,digestion,rumen fermentation and cellulolytic bacterial community of Nubian black goats fed these silages.Banana pseudostem silage was prepared either conventionally without any additives(CON)or mixed with 0.6% formic acid(F),10% corn flour(C),or both(F+C).Four experimental diets containing 40% of the corresponding silages were designed with roughage to concentrate ratio of 50:50(dry matter(DM)basis).A total of 48 Nubian black castrated goats(body weight(BW),(22.64±1.82)kg;4-mon-old)were randomized into one of the four treatment groups with 12 replicates of one castrated goat per replicate for each treatment in a completely randomized design.Each group was fed on one of the four experimental diets for 40 days.A factorial arrangement of treatments of 2(formic acid levels:0 and 0.6%)×2(corn flour:0 and 10%)was adopted.Formic acid supplementation increased(P<0.05)average daily gain,as well as lactic acid,propionate and butyric acid and water-soluble carbohydrate concentrations,but decreased(P<0.05)the feed conversion rate,pH value,acetate/propionate ratio,and butyric acid concentration relative to the CON group.Corn flour supplementation increased(P<0.05)the apparent digestibility of crude protein,neutral detergent fiber,and non-fibrous carbohydrate and Fibrobacter succinogenes,Ruminococcus albus,and Butyrivibrio fibrisolvens populations,but decreased(P<0.05)the Ruminococcus flavefaciens population relative to the CON group.There were no F×C treatment interactions(P>0.05)for any of the other indices except for the apparent digestibility of non-fibrous carbohydrate(NFC)(P<0.05).The results demonstrated that adding 0.6% formic acid and 10% corn flour supplementation to banana pseudostem silages improved the nutritional quality of these silages and enhanced the growth performance of Nubian black castrated goats by improving appare展开更多
In forested stream ecosystems of the north and eastern United States, larvae of the aquatic crane fly Tipula abdominalis are important shredders of leaf litter detritus. T. abdominalis larvae harbor a dense and divers...In forested stream ecosystems of the north and eastern United States, larvae of the aquatic crane fly Tipula abdominalis are important shredders of leaf litter detritus. T. abdominalis larvae harbor a dense and diverse microbial community in their hindgut that may aide in the degradation oflignocellulose. In this study, the activities ofcellulolytic and hemicellulolytic enzymes were demonstrated from hindgut extracts and from bacterial isolates using model sugar substrates. One of the bacterial isolates was further characterized as a member of the family Microbacteriaceae. Taxonomic position of the isolate within this family was determined by a polyphasic approach, as is commonly employed for the separation of genera within the family Microbacteriaceae. The bacterial isolate is Gramtype positive, motile, non-sporulating, and rod-shaped. The G ＋ C content of the DNA is 64.9 mol%. The cell wall contains B2y type peptidoglycan, D- and L-diaminobutyric acid as the diamino acid, and rhamnose as the predominant sugar. The predominant fatty acids are 12-methyltetradecanoic acid （ai-C15：0） and 14-methylhexadecanoic acid （ai-C17：0）. The isolate forms a distinct lineage within the family Microbacteriaceae, as determined by 16S rRNA sequence analysis. We propose the name Crocebacterium ilecola gen. nov., sp. nov., to accommodate this bacterial isolate. The type species is T202T （ATCC BAA-1359; GenBank Accession DQ826511）.展开更多
[Objective] The research aimed to lay the foundation for high-efficiency biological degradation microbial inoculums. [Method] under the 60℃ temperature the cellulolytic microbes in pig manure were isolated and determ...[Objective] The research aimed to lay the foundation for high-efficiency biological degradation microbial inoculums. [Method] under the 60℃ temperature the cellulolytic microbes in pig manure were isolated and determined the CMCase and Fpase,then proceeded the 16S rRNA gene analysis. [Result]The results showed that:BC1 and BC3 strains characterized higher carboxymethyl cellulose enzyme activity and higher filter paper activity,but their difference was small,then the 16S rDNA sequence of BC1 and BC3 strains were related to pseudomonas sp. (98% and 99% similarities,respectively).[Conclusion] the experiment laid foundation for high-efficiency biological heating agent.展开更多
Glucose isomerase(GI)is an enzyme with high potential applications.Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential.Bacillus sp.,Paenarthrobacter sp.,...Glucose isomerase(GI)is an enzyme with high potential applications.Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential.Bacillus sp.,Paenarthrobacter sp.,Chryseobacterium sp.,Hymenobacter sp.,Mycobacterium sp.,and Stenotrophomonas sp.were isolated from soil samples.Optimization of enzyme production yield was investigated in various fermentation conditions using response surface methodology.All isolates exhibited maximum GI activity at 40℃,pH 6–8 after 4 days of incubation.A mixture of peptone/yeast extract or tryptone/peptone enhanced higher enzyme production.The same trend was observed in fermentation medium containing 1%xylose or 2%–2.5%wheat straw.This study advanced the knowledge of these bacterial isolates in promoting wheat straw as feedstock for the bio-based industry.展开更多
利用双层平板法从土壤中分离获得了一株能够降解纤维素的好氧性滑动细菌--生孢噬纤维细菌Sporo-cytophaga sp.JL02,通过菌株基因组DNA的提取、16S r DNA的PCR扩增及克隆、16S r DNA的全序列分析等手段,对该菌株的16S rDNA的基因序列进...利用双层平板法从土壤中分离获得了一株能够降解纤维素的好氧性滑动细菌--生孢噬纤维细菌Sporo-cytophaga sp.JL02,通过菌株基因组DNA的提取、16S r DNA的PCR扩增及克隆、16S r DNA的全序列分析等手段,对该菌株的16S rDNA的基因序列进行了研究。通过扩增,得到了一长度为1560bp的16S rDNA的基因,并对其基因序列进行了分析。展开更多
It is estimated that more than three quarters of the Earth＇s biosphere is in perennially cold environments. Despite the extreme environmental conditions of desiccation and freezing, microbes can colonize these habita...It is estimated that more than three quarters of the Earth＇s biosphere is in perennially cold environments. Despite the extreme environmental conditions of desiccation and freezing, microbes can colonize these habitats through the adaptation of metabolic functions and the synthesis of structurally adapted enzymes. Enzymes within psychrophilic microbes exhibit high specific activity at low and moderate temperature, with low thermostability. In this study we used a classic microbiological approach to isolate Antarctic bacteria with cellulolytic, lipolytic, and ligninolytic activities. From 15 different environmental samples, we generated a collection of approximately 800 bacterial isolates that could grow on R2A or Marine medium at 4℃. This collection was then screened for the presence of the three types of activity at 4℃. We found that 47.7% of the isolates displayed lipolytic activity, 10.2% had cellulase/xylanase activity, and 7.7% showed guaiacol oxidase activity. Of these, 10% displayed two different types of activity, while 0.25% displayed all three types of activity. Our results indicate that cold environments represent outstanding resources for bioprospecting and the study of enzymatic adaptation.展开更多
Myxomycete assemblages were compared on various leaf litters of different vegetation types in a local mixed forest consisting of deciduous and evergreen trees in western Japan. A total of 33 myxomycete species were re...Myxomycete assemblages were compared on various leaf litters of different vegetation types in a local mixed forest consisting of deciduous and evergreen trees in western Japan. A total of 33 myxomycete species were recorded and associated with the chemical and biological environments of leaf litters under natural condition of the forest floor. Different myxomycete assemblages were found on different sites under the dominant trees in a short distance apart (300 m). A site of Prunus jamasakura tree yielded 21 species, a Quercus glauca tree yielded 20 species, an Ilex pedunculosa tree yielded 12 species, and two Quercus serrata trees yielded 13 and 14 species, respectively. Non-metric multidimensional scaling demonstrated that the myxomycete assemblages were closely related to the litter types of deciduous and evergreen trees, and both litter pH and cellulolytic activity influenced distribution of myxomycete species. Species richness was higher in leaf litters with higher pH than in leaf litters with more acidic pH such as I. pedunculosa litter. The dominant tree litter and litter pH strongly influenced the species distribution of foliicolous myxomycetes in a local mixed forest.展开更多
In the present study, the cellulose binding proteins（CBPs） secreted by a putative cellulolytic microbial consortium were isolated and purified by affinity digestion. The purified CBPs were subsequently separated by ...In the present study, the cellulose binding proteins（CBPs） secreted by a putative cellulolytic microbial consortium were isolated and purified by affinity digestion. The purified CBPs were subsequently separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis（SDS-PAGE）. Using mass spectrometric analyses, eight CBPs were identified and annotated to be similar to known proteins secreted by Clostridium clariflavum DSM 19732 and Paenibacillus sp. W-61. In addition, in combination with dilution-to-extinction approach and zymogram analysis technique, CBPs 6（97 k Da） and 12（52 k Da） were confirmed to be the key functional proteins that influence cellulolytic activities. Moreover, structural domain analyses and enzymatic activity detection indicated that CBPs 6 and 12 contained glycoside hydrolase families（GH） 9 and 48 catalytic modules, which both revealed endoglucandase and xylanase activities. It was suggested that the coexistence of GH9 and GH48 catalytic domains present in these two proteins could synergistically promote the efficient degradation of cellulose.展开更多
Poly（lactic acid）-based ternary blends consisting of poly（lactic acid）（PLA）,cellulolytic enzyme lignin（CEL）,and polyolefine grafting maleic anhydride（PGMA） were prepared by extrusion blending and the mechani...Poly（lactic acid）-based ternary blends consisting of poly（lactic acid）（PLA）,cellulolytic enzyme lignin（CEL）,and polyolefine grafting maleic anhydride（PGMA） were prepared by extrusion blending and the mechanical properties and the morphology of the ternary blends were investigated.It was found that the mechanical properties varied with various loading of the components in the blends.Compared to neat PLA,the tensile strength and the Young＇s modulus of the ternary blends were decreased,but the elongation at break and the impact strength were effectively improved.Scanning electron microscope observations revealed that the CEL plays a bridging role between PLA and PGMA,enhancing the miscibility between them and resulting in the improvement of ductility and toughness of the ternary blends.Considering the cost and performance,we obtained the optimal blend PLA/CEL/ PGMA（80/20/20,w/w/w）,of which the impact strength and the elongation at break were doubled as that of neat PLA,and the tensile strength remained moderate.展开更多
The current study has been undertaken to examine the beneficial effect in the power output of a microbial fuel cell (MFC) by adding cellulolytic bacteria Ruminococcus albus (R. albus) into the anodic chamber. Mediator...The current study has been undertaken to examine the beneficial effect in the power output of a microbial fuel cell (MFC) by adding cellulolytic bacteria Ruminococcus albus (R. albus) into the anodic chamber. Mediator-less H-type MFCs were set up where the anode chamber contained anaerobic digester microorganisms as inocula on finely ground pine tree (Avicel) at 2% (w/v) and the cathode chamber of 10mM phosphate buffered saline conductive solution, both separated by a cation exchange membrane. The functioning of the MFCs for generation of electrical power and the amounts of gaseous byproducts was monitored over a 9-day period. The addition of cellulolytic bacteria caused an increase of average power density from 7.9 m W/m2 to19.5 m W/m2, about 245% increase over a 9-day period. For both groups of MFCs;with R. albus and the control, the head space gases collected were methane and CO2. While the methane: CO2 ratios were found unchanged at 1.7:1 throughout the 9 days of operation, the total gas production increased from 248 mL to 319 mL due to the presence of R. albus addition. This study confirms that whereas the biocatalytic activity of anode microbial population determines the energy production, the addition of external cellulolytic bacteria into anode microbial population can improve and extend the biomass utilization.展开更多
Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important i...Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter,remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon(DOC) and soil temperature, but negatively correlated with soil p H. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment(ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils,but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while p H and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota(69.65% in relative abundance) and Basidiomycota(30.35%).Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.展开更多
This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under st...This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under sterilized conditions and incubated at 30 ℃ for 4 to 7 d. The identified fungal species were incubated in self-designed cellulose medium for testing their cellulolytic ability. Forty-two species, including2 nova species, representing sixteen genera showed growth and sporulation in the cellulose medium. Most of the isolated species were from genus Aspergillus and Penicillium. Aspergillus niger and Mucor hiemalis showed highest occurrence frequency （45% and 36% respectively）, as these species were collected from about 80% of soil samples. Being agar free and cheaper, the new fungal medium designed showed results equivalent to Sabouraud medium.展开更多
基金This research was supported by National Natural Science Foundation of China （30671404）, the earmarked fund for Modern Agro-industry Technology Research System of China, the Research Fund for the Doctoral Program of Higher Education of China （200805040010） and the New Zealand Foundation for Research Science and Technology. The authors would also like to thank Sue Zydenbos for editorial assistance.
文摘Cellulose and hemicelluloses are the most prevalent sources of carbon in nature. Currently many approaches employ micro-organisms and their enzyme products to degrade plant feedstocks for production of bioenergy. Scarab larvae are one such model. They consume celluloses from a variety of sources including plant roots, soil organic matter and decaying wood, and are able to extract nutrients and energy from these sources. In this paper, we review the physicochemical properties of the scarab larval gut, the diversity and digestive role that microflora play in the scarab gut and discuss the potential for applying these digestive processes in bioreactors for improving bio-fuel production. Scarab larvae are characterised by their highly alkaline midgut which is dominated by serine proteinase enzymes, and a modified hindgut which harbors the majority of the intestinal microbiota under anaerobic conditions. Evidence suggests that digestion of recalcitrant organic matter in scarab larvae likely results from a combination of endogenous gut proteinases and cellulolytic enzymes produced by symbiotic micro-organisms. Most of the easily digestible proteins are mobilized and absorbed in the midgut by endogenous proteinases. The hindgut contents of scarab larvae are characterized by high concentrations of volatile fatty acids, the presence of fermenting bacteria, and typical anaerobic activities, such as methanogenesis. The hindgut typically contains a wide diversity of micro-organisms, some of which appear to be obligate symbionts with cellulolytic potential. As a result, the scarab larval gut can be regarded as a small bioreactor resembling the rumen of sheep or cattle, where solid food particles composed of cellulose, hemicellulose, pectin and polysaccharides are degraded through enzymatic and fermentation processes. Together these observations suggest scarab larvae have potential to assist the bio-fuel industry by providing new sources of （hemi）cellulolytic bacteria and bacterial （hemi）cellulolytic enzymes.
基金This research was supported by the China Special Fund for Agro-scientific Research in the Public Interest(Investigation on strategies of fattening and high-quality meat productive techniques for herbivores based on resources of unconventional roughage in Southern China)(201303144)the Top Talents Award Plan of Yangzhou University,China(2016,2020)+4 种基金the Cyanine Project of Yangzhou University(2020)the Technology Specialty Fund for Cooperation between Jilin Province and the Chinese Academy of Sciences,2016SYHZ0022)the National Key Research and Development Program of China(2016YFD0700201)the National Natural Science Foundation of China(31902180)the Natural Science Foundation of Jiangsu Province Research Project,China(BK20170488).
文摘The objective of this study was to evaluate the effects of adding formic acid and corn flour supplementation to banana pseudostem silages on the nutritional quality of these silages,growth,digestion,rumen fermentation and cellulolytic bacterial community of Nubian black goats fed these silages.Banana pseudostem silage was prepared either conventionally without any additives(CON)or mixed with 0.6% formic acid(F),10% corn flour(C),or both(F+C).Four experimental diets containing 40% of the corresponding silages were designed with roughage to concentrate ratio of 50:50(dry matter(DM)basis).A total of 48 Nubian black castrated goats(body weight(BW),(22.64±1.82)kg;4-mon-old)were randomized into one of the four treatment groups with 12 replicates of one castrated goat per replicate for each treatment in a completely randomized design.Each group was fed on one of the four experimental diets for 40 days.A factorial arrangement of treatments of 2(formic acid levels:0 and 0.6%)×2(corn flour:0 and 10%)was adopted.Formic acid supplementation increased(P<0.05)average daily gain,as well as lactic acid,propionate and butyric acid and water-soluble carbohydrate concentrations,but decreased(P<0.05)the feed conversion rate,pH value,acetate/propionate ratio,and butyric acid concentration relative to the CON group.Corn flour supplementation increased(P<0.05)the apparent digestibility of crude protein,neutral detergent fiber,and non-fibrous carbohydrate and Fibrobacter succinogenes,Ruminococcus albus,and Butyrivibrio fibrisolvens populations,but decreased(P<0.05)the Ruminococcus flavefaciens population relative to the CON group.There were no F×C treatment interactions(P>0.05)for any of the other indices except for the apparent digestibility of non-fibrous carbohydrate(NFC)(P<0.05).The results demonstrated that adding 0.6% formic acid and 10% corn flour supplementation to banana pseudostem silages improved the nutritional quality of these silages and enhanced the growth performance of Nubian black castrated goats by improving appare
文摘In forested stream ecosystems of the north and eastern United States, larvae of the aquatic crane fly Tipula abdominalis are important shredders of leaf litter detritus. T. abdominalis larvae harbor a dense and diverse microbial community in their hindgut that may aide in the degradation oflignocellulose. In this study, the activities ofcellulolytic and hemicellulolytic enzymes were demonstrated from hindgut extracts and from bacterial isolates using model sugar substrates. One of the bacterial isolates was further characterized as a member of the family Microbacteriaceae. Taxonomic position of the isolate within this family was determined by a polyphasic approach, as is commonly employed for the separation of genera within the family Microbacteriaceae. The bacterial isolate is Gramtype positive, motile, non-sporulating, and rod-shaped. The G ＋ C content of the DNA is 64.9 mol%. The cell wall contains B2y type peptidoglycan, D- and L-diaminobutyric acid as the diamino acid, and rhamnose as the predominant sugar. The predominant fatty acids are 12-methyltetradecanoic acid （ai-C15：0） and 14-methylhexadecanoic acid （ai-C17：0）. The isolate forms a distinct lineage within the family Microbacteriaceae, as determined by 16S rRNA sequence analysis. We propose the name Crocebacterium ilecola gen. nov., sp. nov., to accommodate this bacterial isolate. The type species is T202T （ATCC BAA-1359; GenBank Accession DQ826511）.
基金Supported by Foundation of Henan Educational Committee(2010B530001)~~
文摘[Objective] The research aimed to lay the foundation for high-efficiency biological degradation microbial inoculums. [Method] under the 60℃ temperature the cellulolytic microbes in pig manure were isolated and determined the CMCase and Fpase,then proceeded the 16S rRNA gene analysis. [Result]The results showed that:BC1 and BC3 strains characterized higher carboxymethyl cellulose enzyme activity and higher filter paper activity,but their difference was small,then the 16S rDNA sequence of BC1 and BC3 strains were related to pseudomonas sp. (98% and 99% similarities,respectively).[Conclusion] the experiment laid foundation for high-efficiency biological heating agent.
基金supported by the Natural Science and Engineering Research Council of Canada(NSERC)Discovery Grant(RGPIN-2017-05366)to WQ.
文摘Glucose isomerase(GI)is an enzyme with high potential applications.Characterization of GI producing bacteria with interesting properties from an industrial point of view is essential.Bacillus sp.,Paenarthrobacter sp.,Chryseobacterium sp.,Hymenobacter sp.,Mycobacterium sp.,and Stenotrophomonas sp.were isolated from soil samples.Optimization of enzyme production yield was investigated in various fermentation conditions using response surface methodology.All isolates exhibited maximum GI activity at 40℃,pH 6–8 after 4 days of incubation.A mixture of peptone/yeast extract or tryptone/peptone enhanced higher enzyme production.The same trend was observed in fermentation medium containing 1%xylose or 2%–2.5%wheat straw.This study advanced the knowledge of these bacterial isolates in promoting wheat straw as feedstock for the bio-based industry.
文摘利用双层平板法从土壤中分离获得了一株能够降解纤维素的好氧性滑动细菌--生孢噬纤维细菌Sporo-cytophaga sp.JL02,通过菌株基因组DNA的提取、16S r DNA的PCR扩增及克隆、16S r DNA的全序列分析等手段,对该菌株的16S rDNA的基因序列进行了研究。通过扩增,得到了一长度为1560bp的16S rDNA的基因,并对其基因序列进行了分析。
基金the Antarctic Institute of Uruguay (IAU) Research Projects 2012-2014the National Agency for Innovation and Investigation (ANII) INI_X_2012_1_4201 for partial financial support
文摘It is estimated that more than three quarters of the Earth＇s biosphere is in perennially cold environments. Despite the extreme environmental conditions of desiccation and freezing, microbes can colonize these habitats through the adaptation of metabolic functions and the synthesis of structurally adapted enzymes. Enzymes within psychrophilic microbes exhibit high specific activity at low and moderate temperature, with low thermostability. In this study we used a classic microbiological approach to isolate Antarctic bacteria with cellulolytic, lipolytic, and ligninolytic activities. From 15 different environmental samples, we generated a collection of approximately 800 bacterial isolates that could grow on R2A or Marine medium at 4℃. This collection was then screened for the presence of the three types of activity at 4℃. We found that 47.7% of the isolates displayed lipolytic activity, 10.2% had cellulase/xylanase activity, and 7.7% showed guaiacol oxidase activity. Of these, 10% displayed two different types of activity, while 0.25% displayed all three types of activity. Our results indicate that cold environments represent outstanding resources for bioprospecting and the study of enzymatic adaptation.
文摘Myxomycete assemblages were compared on various leaf litters of different vegetation types in a local mixed forest consisting of deciduous and evergreen trees in western Japan. A total of 33 myxomycete species were recorded and associated with the chemical and biological environments of leaf litters under natural condition of the forest floor. Different myxomycete assemblages were found on different sites under the dominant trees in a short distance apart (300 m). A site of Prunus jamasakura tree yielded 21 species, a Quercus glauca tree yielded 20 species, an Ilex pedunculosa tree yielded 12 species, and two Quercus serrata trees yielded 13 and 14 species, respectively. Non-metric multidimensional scaling demonstrated that the myxomycete assemblages were closely related to the litter types of deciduous and evergreen trees, and both litter pH and cellulolytic activity influenced distribution of myxomycete species. Species richness was higher in leaf litters with higher pH than in leaf litters with more acidic pH such as I. pedunculosa litter. The dominant tree litter and litter pH strongly influenced the species distribution of foliicolous myxomycetes in a local mixed forest.
基金supported by the National Natural Science Foundation of China (No. 31260024)the Science and Technology Support Program of Jiangxi Province (No. 20151BBF60029)+1 种基金the Jiangxi Province Science Foundation (Nos. 20122BAB214012, 20151BAB204001)Science and Technology Project Founded by the Education Department of Jiangxi Province (No. GJJ14297)
文摘In the present study, the cellulose binding proteins（CBPs） secreted by a putative cellulolytic microbial consortium were isolated and purified by affinity digestion. The purified CBPs were subsequently separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis（SDS-PAGE）. Using mass spectrometric analyses, eight CBPs were identified and annotated to be similar to known proteins secreted by Clostridium clariflavum DSM 19732 and Paenibacillus sp. W-61. In addition, in combination with dilution-to-extinction approach and zymogram analysis technique, CBPs 6（97 k Da） and 12（52 k Da） were confirmed to be the key functional proteins that influence cellulolytic activities. Moreover, structural domain analyses and enzymatic activity detection indicated that CBPs 6 and 12 contained glycoside hydrolase families（GH） 9 and 48 catalytic modules, which both revealed endoglucandase and xylanase activities. It was suggested that the coexistence of GH9 and GH48 catalytic domains present in these two proteins could synergistically promote the efficient degradation of cellulose.
文摘Poly（lactic acid）-based ternary blends consisting of poly（lactic acid）（PLA）,cellulolytic enzyme lignin（CEL）,and polyolefine grafting maleic anhydride（PGMA） were prepared by extrusion blending and the mechanical properties and the morphology of the ternary blends were investigated.It was found that the mechanical properties varied with various loading of the components in the blends.Compared to neat PLA,the tensile strength and the Young＇s modulus of the ternary blends were decreased,but the elongation at break and the impact strength were effectively improved.Scanning electron microscope observations revealed that the CEL plays a bridging role between PLA and PGMA,enhancing the miscibility between them and resulting in the improvement of ductility and toughness of the ternary blends.Considering the cost and performance,we obtained the optimal blend PLA/CEL/ PGMA（80/20/20,w/w/w）,of which the impact strength and the elongation at break were doubled as that of neat PLA,and the tensile strength remained moderate.
文摘The current study has been undertaken to examine the beneficial effect in the power output of a microbial fuel cell (MFC) by adding cellulolytic bacteria Ruminococcus albus (R. albus) into the anodic chamber. Mediator-less H-type MFCs were set up where the anode chamber contained anaerobic digester microorganisms as inocula on finely ground pine tree (Avicel) at 2% (w/v) and the cathode chamber of 10mM phosphate buffered saline conductive solution, both separated by a cation exchange membrane. The functioning of the MFCs for generation of electrical power and the amounts of gaseous byproducts was monitored over a 9-day period. The addition of cellulolytic bacteria caused an increase of average power density from 7.9 m W/m2 to19.5 m W/m2, about 245% increase over a 9-day period. For both groups of MFCs;with R. albus and the control, the head space gases collected were methane and CO2. While the methane: CO2 ratios were found unchanged at 1.7:1 throughout the 9 days of operation, the total gas production increased from 248 mL to 319 mL due to the presence of R. albus addition. This study confirms that whereas the biocatalytic activity of anode microbial population determines the energy production, the addition of external cellulolytic bacteria into anode microbial population can improve and extend the biomass utilization.
基金supported by the Natural National Science Foundation of China (No. 41771303)Chinese Academy of Sciences (Nos. QYZDB-SSW-DQC033, XDB15010203 and XDA19070304)。
文摘Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter,remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon(DOC) and soil temperature, but negatively correlated with soil p H. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment(ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils,but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while p H and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota(69.65% in relative abundance) and Basidiomycota(30.35%).Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.
文摘This study is aimed at identifying and determining the percentage of occurrence frequency of cellulose decomposing soil fungi. The soil samples were inoculated into culture plates prepared in Sabouraud medium under sterilized conditions and incubated at 30 ℃ for 4 to 7 d. The identified fungal species were incubated in self-designed cellulose medium for testing their cellulolytic ability. Forty-two species, including2 nova species, representing sixteen genera showed growth and sporulation in the cellulose medium. Most of the isolated species were from genus Aspergillus and Penicillium. Aspergillus niger and Mucor hiemalis showed highest occurrence frequency （45% and 36% respectively）, as these species were collected from about 80% of soil samples. Being agar free and cheaper, the new fungal medium designed showed results equivalent to Sabouraud medium.
