An extracellular polyhydroxybutyrate（PHB） depolymerase was purified to homogeneity from the culture supernatant of a PHB-degrading bacterium, Pseudomonas mendocina DSWY0601, which was isolated from brewery sewage fo...An extracellular polyhydroxybutyrate（PHB） depolymerase was purified to homogeneity from the culture supernatant of a PHB-degrading bacterium, Pseudomonas mendocina DSWY0601, which was isolated from brewery sewage for the ability to form clear zones on the PHB mineral agar plates. The molecular weight of the purified PHB depolymerase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE） was ap- proximately 59800 at the optimal temperature and pH value being 50 ℃ and 8.5, respectively. PHB depolymerase was stable in a temperature range of 20--50 ℃ and sensitive to pH value within a pH range of 8.0-9.5. PHB depo- lymerase degraded poly-3-hydroxybutyrate-co-4-hydroxybutyrate（P3/4HB） and poly-3-hydroxybutyrate-co-3- hydroxyvalerate（PHBV） but did not degrade poly（lactic acid）（PLA）, poly（butylene succinate）（PBS） or poly- （caprolactone）（PCL）. PHB depolymerase was sensitive to phenylmethylsulfonyl fluoride（PMSF）, H202 and SDS. The main product after enzymatic degradation of PHB was indentified as 3-hydroxbutyrate monomer（3HB） by mass spectrometric analysis, suggesting that PHB depolymerase acted as an exo-type hydrolase. Analysis ofphaZpm gene reveals that PHB depolymerase is a typical denatured short-chain-length PHA（dPHAscL, PHA=polyhydroxyalkanoate） depolymerase containing catalytic domain, linker and substrate-binding domain.展开更多
为探究全球聚羟基烷酸酯(PHA)研究的学者科研合作紧密度、时空特征和未来趋势,基于文献计量可视化分析软件CiteSpace,以Web of Science(WoS)数据库为数据源,对2013—2022年收录的论文进行学者科研合作的归纳分析。研究结果表明:2013—2...为探究全球聚羟基烷酸酯(PHA)研究的学者科研合作紧密度、时空特征和未来趋势,基于文献计量可视化分析软件CiteSpace,以Web of Science(WoS)数据库为数据源,对2013—2022年收录的论文进行学者科研合作的归纳分析。研究结果表明:2013—2022年聚羟基烷酸酯研究的科研合作紧密度较小,全球范围的合作较为松散,合作关系存在明显的个人、机构和地缘指向特征,合作关系表现出“强强合作”的特征,并且合作机构以高校为主,其中实力雄厚的研究机构发文量相对也较高;发文量最多的国家依次是中国、印度、美国、意大利和西班牙,其中美国的发文量虽高,但研究者人数较少,成果基本集中于部分高产研究者。今后,研究者不仅要注重地区之间的合作,还应注意学科之间的合作,跨地域、跨学科可以增加研究驱动力。展开更多
Four sequence batch reactors（SBRs） fed by fermented sugar cane wastewater were continuously operated under the aerobic dynamic feeding（ADF） mode with different configurations of sludge retention time（SRT）, carbo...Four sequence batch reactors（SBRs） fed by fermented sugar cane wastewater were continuously operated under the aerobic dynamic feeding（ADF） mode with different configurations of sludge retention time（SRT）, carbon and initial biomass concentrations to enrich polyhydroxyalkanoate（PHA） accumulating mixed microbial cultures（MMCs） from municipal activated sludge.The stability of SBRs was investigated besides the enrichment performance. The microbial community structures of the enriched MMCs were analyzed using terminal restriction fragment length polymorphism（T-RFLP）. The optimum operating conditions for the enrichment process were： SRT of 5 days, carbon concentration of 2.52 g COD/L and initial biomass concentration of3.65 g/L. The best enrichment performance in terms of both operating stability and PHA storage ability of enriched cultures（with the maximum PHA content and PHA storage yield（YPHA/S） of61.26% and 0.68 mg COD/mg COD, respectively） was achieved under this condition. Effects of the SRT, carbon concentration and initial biomass concentration on the PHA accumulating MMCs selection process were discussed respectively. A new model including the segmentation of the enrichment process and the effects of SRT on each phase was proposed.展开更多
After polyhydroxyalkanoate (PHA) fermentation for 42 - 48 h by the Azotobacter chroococcum G-3, the PHA content reached more than 75% of the dry weight. Biomass was isolated from culture by centrifugation and pretreat...After polyhydroxyalkanoate (PHA) fermentation for 42 - 48 h by the Azotobacter chroococcum G-3, the PHA content reached more than 75% of the dry weight. Biomass was isolated from culture by centrifugation and pretreated with freezing to release PHA pellet, then was treated with 10 g/L sodium dodecyl sulfate (SDS) for 15 min to effectively solubilize lipid and protein. Subsequently, it was further purified by digesting with 30% sodium hypochlorite (NaCIO) for 3 min to remove peptidoglycan and non-PHA biomass. Finally, 98% PHA was obtained by diluting and rinsing with water, and the PHA recovered was suitable for processing.展开更多
基金Supported by the National Natural Science Foundation of China (Nos.31100046,31100099)
文摘An extracellular polyhydroxybutyrate（PHB） depolymerase was purified to homogeneity from the culture supernatant of a PHB-degrading bacterium, Pseudomonas mendocina DSWY0601, which was isolated from brewery sewage for the ability to form clear zones on the PHB mineral agar plates. The molecular weight of the purified PHB depolymerase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE） was ap- proximately 59800 at the optimal temperature and pH value being 50 ℃ and 8.5, respectively. PHB depolymerase was stable in a temperature range of 20--50 ℃ and sensitive to pH value within a pH range of 8.0-9.5. PHB depo- lymerase degraded poly-3-hydroxybutyrate-co-4-hydroxybutyrate（P3/4HB） and poly-3-hydroxybutyrate-co-3- hydroxyvalerate（PHBV） but did not degrade poly（lactic acid）（PLA）, poly（butylene succinate）（PBS） or poly- （caprolactone）（PCL）. PHB depolymerase was sensitive to phenylmethylsulfonyl fluoride（PMSF）, H202 and SDS. The main product after enzymatic degradation of PHB was indentified as 3-hydroxbutyrate monomer（3HB） by mass spectrometric analysis, suggesting that PHB depolymerase acted as an exo-type hydrolase. Analysis ofphaZpm gene reveals that PHB depolymerase is a typical denatured short-chain-length PHA（dPHAscL, PHA=polyhydroxyalkanoate） depolymerase containing catalytic domain, linker and substrate-binding domain.
文摘为探究全球聚羟基烷酸酯(PHA)研究的学者科研合作紧密度、时空特征和未来趋势,基于文献计量可视化分析软件CiteSpace,以Web of Science(WoS)数据库为数据源,对2013—2022年收录的论文进行学者科研合作的归纳分析。研究结果表明:2013—2022年聚羟基烷酸酯研究的科研合作紧密度较小,全球范围的合作较为松散,合作关系存在明显的个人、机构和地缘指向特征,合作关系表现出“强强合作”的特征,并且合作机构以高校为主,其中实力雄厚的研究机构发文量相对也较高;发文量最多的国家依次是中国、印度、美国、意大利和西班牙,其中美国的发文量虽高,但研究者人数较少,成果基本集中于部分高产研究者。今后,研究者不仅要注重地区之间的合作,还应注意学科之间的合作,跨地域、跨学科可以增加研究驱动力。
基金supported by the National Natural Science Foundation of China(No.51378142)the Program for New Century Excellent Talents in University(No.NCET-12-0156)+1 种基金the Open Project of the State Key Laboratory of Urban Water ResourceEnvironment(Harbin institute of Technology)(No.2015DX10)
文摘Four sequence batch reactors（SBRs） fed by fermented sugar cane wastewater were continuously operated under the aerobic dynamic feeding（ADF） mode with different configurations of sludge retention time（SRT）, carbon and initial biomass concentrations to enrich polyhydroxyalkanoate（PHA） accumulating mixed microbial cultures（MMCs） from municipal activated sludge.The stability of SBRs was investigated besides the enrichment performance. The microbial community structures of the enriched MMCs were analyzed using terminal restriction fragment length polymorphism（T-RFLP）. The optimum operating conditions for the enrichment process were： SRT of 5 days, carbon concentration of 2.52 g COD/L and initial biomass concentration of3.65 g/L. The best enrichment performance in terms of both operating stability and PHA storage ability of enriched cultures（with the maximum PHA content and PHA storage yield（YPHA/S） of61.26% and 0.68 mg COD/mg COD, respectively） was achieved under this condition. Effects of the SRT, carbon concentration and initial biomass concentration on the PHA accumulating MMCs selection process were discussed respectively. A new model including the segmentation of the enrichment process and the effects of SRT on each phase was proposed.
文摘After polyhydroxyalkanoate (PHA) fermentation for 42 - 48 h by the Azotobacter chroococcum G-3, the PHA content reached more than 75% of the dry weight. Biomass was isolated from culture by centrifugation and pretreated with freezing to release PHA pellet, then was treated with 10 g/L sodium dodecyl sulfate (SDS) for 15 min to effectively solubilize lipid and protein. Subsequently, it was further purified by digesting with 30% sodium hypochlorite (NaCIO) for 3 min to remove peptidoglycan and non-PHA biomass. Finally, 98% PHA was obtained by diluting and rinsing with water, and the PHA recovered was suitable for processing.
