摘要
我国广大地区的冬季低温持续时间长.低温可抑制微生物生长代谢,使好氧堆肥的堆体无法升温,导致纤维素类生物质废弃物好氧堆肥启动困难甚至失败,同时使得木质纤维素降解缓慢,延长堆肥周期,增加生产成本.因此筛选耐低温的高效纤维素降解菌,保障在低温条件下纤维素类生物质废弃物的好氧堆肥顺利启动,对解决这一难题具有重要的意义.采用可培养方法筛选了一株高效的纤维素降解菌Aspergillus fumigatus strain F7,该菌株能在羧甲基纤维素钠刚果红平板上生长,生长温度范围广(15-50℃),并可生成水解透明圈.同时表现出良好的内切葡聚糖酶活、外切葡聚糖酶活和滤纸酶活,表明该菌具有完整的纤维素降解酶系.进一步构建该菌的全基因组草图,分析发现A.fumigatus strain F7含有与纤维素降解相关的基因12种,可编码半纤维素、纤维素和木质素降解酶.含有与低温耐受相关的基因20种,能够改善细胞膜流动性和生成保护细胞的化合物.含有与高温耐受相关的基因15种,主要编码热休克蛋白、超氧化物歧化酶和参与海藻糖代谢的酶.这3类预测的基因多数在不同底物和不同培养温度条件下的转录水平表现出差异,进一步表明基因组草图对菌株潜力的预测结果较为可靠,这些基因可能参与A.fumigatus strain F7的木质纤维素降解和温度适应等功能.本研究表明A.fumigatus strain F7在纤维素类废弃物的好氧堆肥中具有良好的应用潜力.
In winter,low temperatures could inhibit the growth and metabolism of microorganisms and prevent heaps of compost from heating up,leading to failed start-ups of aerobic composting of cellulosic biomass waste.At the same time,low lignocellulose degradation efficiency would result in a long composting cycle and high production cost.Therefore,it is of great importance to screen microorganisms with low-temperature resistance and efficient cellulose-degrading ability to ensure the successful start of aerobic composting of cellulosic biomass waste under low temperature conditions.A highly efficient cellulose-degrading fungus,Aspergillus fumigatus strain F7,was screened and characterized in this study.It grew on sodium carboxymethyl cellulose(CMC-Na)and Congo red plates over a wide temperature(15–50℃)and formed hydrolytic transparent circles.The cellulase activities of A.fumigatus strain F7 were detected on substrates of CMC-Na,microcrystalline cellulose,and filter paper,indicating that A.fumigatus strain F7 had a complete cellulolytic enzyme system.In addition,the analysis of the genome sketch of A.fumigatus strain F7 showed that there were 12 types of genes related to cellulose degradation,which encoded enzymes degrading hemicellulose,cellulose,and lignin.Moreover,there were 20 types of genes related to low-temperature adaptation,which could primarily improve cell membrane fluidity and produce compounds that could protect cells at low temperatures.There were 15 types of genes related to high temperature tolerance,encoding heat shock proteins,superoxide dismutase,and enzymes involved in trehalose metabolism.Most of the three types of predicted genes showed differences at the transcription level under different substrates and temperature conditions,further indicating that the prediction of functional potential was credible through the draft genome.These genes may be involved in the degradation of lignocellulose and temperature adaptation.Therefore,A.fumigatus strain F7 showed good application potential in the aerobi
作者
杨涛
贾晓君
秦晓萌
赵源
田雪平
邓蓉
黄钧
YANG Tao;JIA Xiaojun;QIN Xiaomeng;ZHAO Yuan;TIAN Xueping;DENG Rong;HUANG Jun(CAS Key Laboratory of Environmental and Applied Microbiology,Environmental Microbiology Key Laboratory of Sichuan Province,Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Life Sciences,Sichuan University,Chengdu 610041,China)
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2022年第1期190-200,共11页
Chinese Journal of Applied and Environmental Biology
基金
国家重点研发计划项目(2017YFC0505005-4)资助。
关键词
烟曲霉
纤维素降解
低温适应
高温耐受
基因组草图
Aspergillus fumigatus
cellulose degradation
low temperature adaptation
high temperature resistance
genome sketch
