Wang Na, Yan Zhihua, Liu Na, Zhang Xiaorong, Xu Chenggang
Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Biotechnology, Shanxi University, Taiyuan 030006, China.
Microorganisms. 2022 Feb 24;10(3):502. doi: 10.3390/microorganisms10030502.
Anaerobes harbor some of the most efficient biological machinery for cellulose degradation, especially thermophilic bacteria, such as and , which play a fundamental role in transferring lignocellulose into ethanol through consolidated bioprocessing (CBP). In this study, we compared activities of two cellulase systems under varying kinds of hemicellulose and cellulose. was identified to contribute specifically to cellulose hydrolysis, whereas contributes to hemicellulose hydrolysis. The two systems were assayed in various combinations to assess their synergistic effects using cellulose and corn stover as the substrates. Their maximum synergy degrees on cellulose and corn stover were, respectively, 1.26 and 1.87 at the ratio of 3:2. Furthermore, co-culture of these anaerobes on the mixture of cellulose and xylan increased ethanol concentration from 21.0 to 40.4 mM with a high cellulose/xylan-to-ethanol conversion rate of up to 20.7%, while the conversion rates of and monocultures were 19.3% and 15.2%. The reason is that had the ability to rapidly degrade cellulose while co-utilized both pentose and hexose, the metabolites of cellulose degradation, to produce ethanol. The synergistic effect of cellulase systems and metabolic pathways in and provides a novel strategy for the design, selection, and optimization of ethanol production from cellulosic biomass through CBP.
厌氧菌拥有一些用于纤维素降解的最高效生物机制，尤其是嗜热细菌，如[具体细菌名称1]和[具体细菌名称2]，它们在通过联合生物加工（CBP）将木质纤维素转化为乙醇的过程中发挥着重要作用。在本研究中，我们比较了两种纤维素酶系统在不同种类半纤维素和纤维素条件下的活性。[酶1名称]被确定对纤维素水解有特异性贡献，而[酶2名称]则有助于半纤维素水解。以纤维素和玉米秸秆为底物，对这两种系统进行了各种组合测定，以评估它们的协同作用。在3:2的比例下，它们在纤维素和玉米秸秆上的最大协同度分别为1.26和1.87。此外，这些厌氧菌在纤维素和木聚糖混合物上的共培养使乙醇浓度从21.0 mM提高到40.4 mM，纤维素/木聚糖到乙醇的转化率高达20.7%，而[细菌1名称]和[细菌2名称]单培养的转化率分别为19.3%和15.2%。原因是[细菌1名称]有能力快速降解纤维素，而[细菌2名称]共同利用纤维素降解的代谢产物戊糖和己糖来生产乙醇。[细菌1名称]和[细菌2名称]中纤维素酶系统和代谢途径的协同作用为通过CBP从纤维素生物质生产乙醇的设计、选择和优化提供了一种新策略。
