Bhalla Aditya, Arce Jessie, Ubanwa Bryan, Singh Gursharan, Sani Rajesh K, Balan Venkatesh
Department of Chemical and Biological Engineering, South Dakota School of Mines and Technology, Rapid City, SD, United States.
Department of Chemistry, Biology and Health Science, South Dakota School of Mines and Technology, Rapid City, SD, United States.
Front Microbiol. 2022 May 25;13:844287. doi: 10.3389/fmicb.2022.844287. eCollection 2022.
A thermophilic bacterial strain, WSUCF1 contains different carbohydrate-active enzymes (CAZymes) capable of hydrolyzing hemicellulose in lignocellulosic biomass. We used proteomic, genomic, and bioinformatic tools, and genomic data to analyze the relative abundance of cellulolytic, hemicellulolytic, and lignin modifying enzymes present in the secretomes. Results showed that CAZyme profiles of secretomes varied based on the substrate type and complexity, composition, and pretreatment conditions. The enzyme activity of secretomes also changed depending on the substrate used. The secretomes were used in combination with commercial and purified enzymes to carry out saccharification of ammonia fiber expansion (AFEX)-pretreated corn stover and extractive ammonia (EA)-pretreated corn stover. When WSUCF1 bacterial secretome produced at different conditions was combined with a small percentage of commercial enzymes, we observed efficient saccharification of EA-CS, and the results were comparable to using a commercial enzyme cocktail (87% glucan and 70% xylan conversion). It also opens the possibility of producing CAZymes in a biorefinery using inexpensive substrates, such as AFEX-pretreated corn stover and Avicel, and eliminates expensive enzyme processing steps that are used in enzyme manufacturing. Implementing in-house enzyme production is expected to significantly reduce the cost of enzymes and biofuel processing cost.
嗜热细菌菌株WSUCF1含有不同的碳水化合物活性酶（CAZymes），能够水解木质纤维素生物质中的半纤维素。我们使用蛋白质组学、基因组学和生物信息学工具以及基因组数据来分析分泌组中存在的纤维素分解酶、半纤维素分解酶和木质素修饰酶的相对丰度。结果表明，分泌组的CAZyme谱根据底物类型、复杂性、组成和预处理条件而有所不同。分泌组的酶活性也因所用底物而异。分泌组与商业酶和纯化酶结合使用，对氨纤维膨胀（AFEX）预处理的玉米秸秆和抽提氨（EA）预处理的玉米秸秆进行糖化。当在不同条件下产生的WSUCF1细菌分泌组与一小部分商业酶结合使用时，我们观察到EA-CS的高效糖化，结果与使用商业酶混合物相当（葡聚糖转化率为87%，木聚糖转化率为70%）。这也为在生物精炼厂中使用廉价底物（如AFEX预处理的玉米秸秆和微晶纤维素）生产CAZymes开辟了可能性，并消除了酶制造中使用的昂贵酶加工步骤。实施内部酶生产有望显著降低酶成本和生物燃料加工成本。
