发酵水稻秸秆产酸复合菌群的筛选与评价

 为开发秸秆发酵生产有机挥发酸的微生物种子资源和研究材料,以牛粪、猪粪堆肥、玉米地土壤、腐木以及猪粪堆肥和腐木混合物为接种物,通过传代富集培养,选育到发酵水稻秸秆产酸性能相对稳定的5个复合菌群,即FM_c、FM_d、FM_s、FM_w和FM_(d+w).经测试,FM_w具有最高的秸秆降解能力,其秸秆降解率可达46.4%;菌群FM_(d+w)发酵秸秆的总酸和丁酸比产率最高,分别为0.64和0.48g/g;发酵秸秆产乙酸能力以菌群FM_d最为突出,其乙酸比产率为0.35g/g.5个复合菌群均缺乏酸性纤维素酶活性,极大限制了秸秆降解率和产酸率,需要进一步的耐酸驯化和培养条件优化.

Breeding and Selection of Mixed Bacterial Cultures for Volatile Fatty Acid Production by Rice Straw Fermentation

To develop genetic resources for microorganisms and to study the volatile fatty acid production by rice straw fermentation, mixed bacterial cultures FM_c, FM_d, FM_s, FM_w and FM_(d+w) were obtained by subculture with cow muck, pig compost soil, rotten wood, and mixture of pig compost soil and rotten wood as inoculums. Among the five mixed cultures, FM_w shows the highest straw degradation rate of 46.4%. The highest specific production rates of the total volatile fatty acid and the total butyric acid from rice straw are reached by the mixed culture FM_(d+w) with a value of 0.64 and 0.48g/g, respectively. The mixed culture FM_d produces more acetic acid from rice straw than others with a specific yield of 0.35g/g. It is found that the five mixed bacterial cultures all lack the acidity glucanase, resulting in a great restriction in the degradation of rice straw and the fatty acid yield. In order to improve the mixed cultures with respect to their fatty acid yield, a domestication to fatty acids and an optimization of cultivation conditions are desirable.