五株木糖利用酵母的生理代谢特性

Physiological and metabolic characteristics of five xylose utilizing yeasts

摘要:

摘要:【目的】木质纤维素是地球上最丰富的可再生资源，筛选具有高抗逆和高效利用木糖能力的菌株对纤维素类可再生资源综合利用具有重大意义。【方法】论文以5株利用木糖的酵母，即树干毕赤酵母(Scheffersomyces stipitis，S.stipitis)、Candida tenuis (C.tenuis)、Spathaspora passalidarum (S.passalidarum)、Candida amazonensis(C. amazonensis)和Candida jeffriesii(C. jeffriesii)为研究对象，研究了其对温度、乙醇浓度、渗透压的耐受性，采用杜氏小管实验研究了其对常用碳源和氮源的利用能力，另外通过木糖发酵实验初步研究了被测试酵母在有氧和限氧条件下的木糖发酵性能。【结果】结果表明，S. passalidarum能够耐受44 ℃左右的高温，对多种碳源和氮源具有较强的利用能力，此外，S. passalidarum在有氧与限氧条件下均能快速代谢木糖，限氧条件下乙醇得率达0.43 g/g。C. amazonensis对纤维二糖具有较强发酵能力，代谢木糖产生木糖醇和少量乙醇，同时该酵母耐受温度在42 ℃左右。综合比较，其他酵母在实验过程中没有表现出明显优势。【结论】S. passalidarum 在纤维素工业化应用中是一株良好的生产候选菌株。此外，C. amazonensis具有较强的木糖醇生产能力，有望成为一株优良的木糖醇生产菌株。

Abstract:

Abstract:［Objective］It is of great significance to improve the utilization of lignocellulosic material，the most abundant renewable resource on earth.［Methods］We studied the stress tolerance (temperature，ethanol and osmotic tolerance) of five xylose utilizing yeasts，Scheffersomyces stipitis，Candida tenuis，Spathaspora passalidarum，Candida amazonensis and Candida jeffriesii．We also tested their utilization ability of multiple carbon and nitrogen sources.［Results］ S．passalidarum could tolerate at 44C and utilize various carbon and nitrogen sources effectively. S．passalidarum could metabolism xylose rapidly to produce ethanol，with an ethanol yield of 0.43 g/g under oxygen limiting condition． C．amazonensis could also torelate at 42C．Moreover，C．amazonensis could converse xylose to xylitol with ethanol as the main by-product.［Conclusion］ S．passalidarum is a potentially valuable workhorse in industrial utilization of lignocellulosic for its excellent characteristics． In addition，C．amazonensis may be a promising xylitol producer．