Characterization of a Defined Cellulolytic and Xylanolytic Bacterial Consortium for Bioprocessing of Cellulose and Hemicelluloses
Characterization of a Defined Cellulolytic and Xylanolytic Bacterial Consortium for Bioprocessing of Cellulose and Hemicelluloses
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DOI：
10.1007/s12010-010-9091-0
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发表时间：
2011-04-01
影响因子：
3
通讯作者：
Lu, Jue
中科院分区：
文献类型：
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作者：
Okeke, Benedict C.;Lu, Jue
化石燃料储备的减少和化石碳氢化合物产品成本的增加重新点燃了全世界将木质纤维素（植物生物质）转化为可再生燃料的努力。草、农业和伐木残留物等不可食用的植物材料是丰富的可再生自然资源，可以转化为生物燃料。为了在木质纤维素生物加工中模拟天然纤维素分解-木聚糖分解微生物群落，我们富集了纤维素分解-木聚糖分解微生物，纯化了 19 种单一培养物并评估了它们的纤维素分解-木聚糖分解潜力。五个选定的分离株（DB1、DB2、DB7、DB8 和 DB13）用于组成一个确定的联合体，并通过 16S 核糖体 RNA 基因序列分析进行表征。核苷酸序列比对分析显示，DB1、DB2、DB7、DB8 和 DB13 分别与 Pseudoxanthomonas byssovorax (99%)、Microbacter oxydans (99%)、Bacillus sp. 相似。 (99%)、人苍白杆菌 (98%) 和特雷维萨克雷伯菌 (99%)。这些分离株产生一系列纤维素分解-木聚糖分解酶（滤纸纤维素酶、β-葡萄糖苷酶、木聚糖酶和 β-木糖苷酶），并在 30 分钟内记录到显着的活性。分离株DB1和DB2显示出最高的滤纸纤维素酶：分别为27.83和31.22 Umg(-1)。在菌株DB1的培养物中检测到最高的β-葡萄糖苷酶活性(18.07 Umg(-1))。分离株DB2产生最高的木聚糖酶活性(103.05 Umg(-1))，而DB13观察到最高的β-木糖苷酶活性(7.72 Umg(-1))。在木质纤维素的生物加工中使用微生物群落可以减少诸如不完全协同酶、终产物抑制、吸附以及直接使用酶需要大量酶等问题。
Diminishing fossil fuel reserve and increasing cost of fossil hydrocarbon products have rekindled worldwide effort on conversion of lignocellloloses (plant biomass) to renewable fuel. Inedible plant materials such as grass, agricultural, and logging residues are abundant renewable natural resources that can be converted to biofuel. In an effort to mimic natural cellulolytic-xylanolytic microbial community in bioprocessing of lignocelluloses, we enriched cellulolytic-xylanolytic microorganisms, purified 19 monocultures and evaluated their cellulolytic-xylanolytic potential. Five selected isolates (DB1, DB2, DB7, DB8, and DB13) were used to compose a defined consortium and characterized by 16S ribosomal RNA gene sequence analysis. Nucleotide sequence blast analysis revealed that DB1, DB2, DB7, DB8, and DB13 were respectively similar to Pseudoxanthomonas byssovorax (99%), Microbacterium oxydans (99%), Bacillus sp. (99%), Ochrobactrum anthropi (98%), and Klebsiella trevisanii (99%). The isolates produced an array of cellulolytic-xylanolytic enzymes (filter paper cellulase, beta-glucosidase, xylanase, and beta-xylosidase), and significant activities were recorded in 30 min. Isolates DB1 and DB2 displayed the highest filter paper cellulase: 27.83 and 31.22 Umg(-1), respectively. The highest beta-glucosidase activity (18.07 Umg(-1)) was detected in the culture of isolate DB1. Isolate DB2 produced the highest xylanase activity (103.05 Umg(-1)), while the highest beta-xylosidase activity (7.72 Umg(-1)) was observed with DB13. Use of microbial consortium in bioprocessing of lignocelluloses could reduce problems such as incomplete synergistic enzymes, end-product inhibition, adsorption, and requirement for high amounts of enzymes in direct use of enzymes.