Clostridium autoethanogenum is an autotrophic acetogen also able to utilize xylose as a carbon source. Here, we evaluated this organism's industrially relevant capability since the transformation of sugars derived from lignocellulosic materials to biofuels is of great interest. Initially, the organism was challenged with different initial xylose levels to determine xylose utilization and maximum inhibitory concentrations for C. autoethanogenum when grown in batch cultures. A critical factor that could limit xylose utilization is culture pH, and this factor was separately examined as a means to provide C. autoethanogenum with more suitable environmental conditions. Finally, optimum pH conditions for growth were tested to assess how efficiently initial xylose concentrations could be fully utilized. C. autoethanogenum specific growth rate was not impacted when cells were exposed to initial xylose concentrations up to 30 g L⁻¹, while cultures amended with concentrations as high as 45 g L⁻¹ showed a delay in growth and in formation of final fermentation product concentrations. Intermittent adjustment of the culture pH to 5.8 allowed for complete substrate utilization when step-wise fed-batch xylose additions were performed. Under these conditions the cultures showed a unique biphasic growth which enhanced biomass and end product formation. In C. autoethanogenum cultures exposed to an initial xylose concentration as high as 30 g L⁻¹, pH adjustment to 5.8 supported full utilization of all available xylose and generation of up to 2.4 g L⁻¹ ethanol and 9.5 g L⁻¹ acetate. This work demonstrated that C. autoethanogenum can effectively biotransform xylose at concentrations typically present in lignocellulosic hydrolysate streams.

自产乙醇梭菌是一种自养型产乙酸菌，也能够利用木糖作为碳源。在这里，我们评估了这种生物的工业相关能力，因为将木质纤维素材料中的糖转化为生物燃料引起了人们的极大兴趣。最初，在分批培养物中生长时，用不同的初始木糖水平挑战生物体以确定木糖利用率和自产乙醇梭菌的最大抑制浓度。可能限制木糖利用的一个关键因素是培养液的pH值，并且对该因素进行了单独检查，以作为提供C. autoethanogenum的手段。具有更合适的环境条件 最后，测试了生长的最佳pH条件，以评估如何充分利用初始木糖浓度。当细胞暴露于最高达30 g L ^-1的初始木糖浓度下时，自身乙型梭菌的比生长速率不受影响，而浓度高达45 g L ^-1修正的培养物则显示出生长延迟和最终发酵产物的形成浓度。当逐步添加分批补料木糖时，将培养液的pH值间歇调节至5.8，可以完全利用底物。在这些条件下，培养物显示出独特的双相生长，从而增强了生物量和最终产物的形成。在C.autoethanogenum暴露于高达30 g L ^-1的初始木糖浓度，pH调节至5.8的培养物可充分利用所有可用的木糖，并生成多达2.4 g L ^-1的乙醇和9.5 g L ^-1的乙酸盐。这项工作证明自产乙醇梭菌可以在木质纤维素水解产物流中通常存在的浓度下有效地生物转化木糖。