Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
Bioresour Technol. 2014;152:384-92. doi: 10.1016/j.biortech.2013.11.024. Epub 2013 Nov 19.
The thermophilic bacterium Caldicellulosiruptor bescii grows at 78 °C on high concentrations (200 g L(-1)) of both crystalline cellulose and unpretreated switchgrass, while low concentrations (<20 g L(-1)) of acid-pretreated switchgrass inhibit growth. Degradation of crystalline cellulose, but not that of unpretreated switchgrass, was limited by nitrogen and vitamin (folate) availability. Under optimal conditions, C. bescii solubilized approximately 60% of the crystalline cellulose and 30% of the unpretreated switchgrass using initial substrate concentrations of 50 g L(-1). Further fermentation of crystalline cellulose and of switchgrass was inhibited by organic acid end-products and by a specific inhibitor of C. bescii growth that did not affect other thermophilic bacteria, respectively. Soluble mono- and oligosaccharides, organic acids, carbon dioxide, and microbial biomass, quantitatively accounted for the crystalline cellulose and plant biomass carbon utilized. C. bescii therefore degrades industrially-relevant concentrations of lignocellulosic biomass that have not undergone pretreatment thereby demonstrating its potential utility in biomass conversion.
嗜热细菌 Caldicellulosiruptor bescii 在 78°C 下能以高浓度（200 g/L）的结晶纤维素和未经预处理的柳枝稷生长，而低浓度（<20 g/L）的酸预处理柳枝稷则会抑制生长。结晶纤维素的降解，但未经预处理的柳枝稷的降解，受到氮和维生素（叶酸）供应的限制。在最佳条件下，C. bescii 用初始底物浓度为 50 g/L 时，大约溶解了 60%的结晶纤维素和 30%的未经预处理的柳枝稷。进一步发酵结晶纤维素和柳枝稷分别受到有机酸终产物和一种特定的 C. bescii 生长抑制剂的抑制，该抑制剂不影响其他嗜热细菌。可溶性单糖和寡糖、有机酸、二氧化碳和微生物生物量，定量地解释了结晶纤维素和植物生物质碳的利用情况。因此，C. bescii 降解了未经预处理的具有工业相关性浓度的木质纤维素生物质，从而证明了其在生物质转化中的潜在用途。
