棉秆的微生物降解及糖化工艺研究

用2株放线菌J71、J74对经一定预处理的棉秆进行降解,首先检测了2株菌降解棉秆纤维的酶活动力学,结果表明,一定检测周期内,2株菌对棉秆有较强的降解作用,其酶活高峰期均出现在第6 d。以棉秆作为唯一碳源,研究了不同氮源:(NH4)2SO40.1%、0.2%、0.5%,尿素0.1%、0.2%、0.5%,10%麸皮汁对菌株产酶能力的影响。结果显示,以10%麸皮汁为氮源时,J71和J74降解棉秆的CMC酶活、FPA酶活及糖化率最高。通过正交试验检测了发酵影响因子棉秆粒径、发酵液起始pH、发酵温度和发酵时间对菌株J71和J74降解棉秆糖化率的影响,得出了棉秆糖化较优的工艺参数,即将棉秆制成10目粒径的颗粒,维持发酵液在pH 5.0～6.0,于37℃发酵9 d,能获得较高的糖化率。

Degradation and Glycosylated Technics of Cotton Stalk by Microbes

Two Streptomyces J71 and J74 were used to degrade cotton stalks pretreated by dilute-sulfuric acid.Cellulase activity dynamics of cotton stalk fiber degradation was examined.The results showed that in certain periods,these strains effectively degraded cotton stalk and the highest cellulase activity presented on the sixth day.Using cotton stalk as the only carbon source,different nitrogen sources((NH4)2SO4 0.1%,0.2%,0.5%,carbamide 0.1%,0.2%,0.5% and 10% bran extract) were set to study the effects on these strains' ability to produce cellulase.The results revealed that taking 10% bran extract as nitrogen source,J71 and J74 reached the highest CMCase,FPase and glycosylated ratio.Orthogonal test was designed for examining effects of fermentation factors material size,pH value,temperature and fermentation time on glycosylated ratio in cotton stalk degradation,optimum fermentation technical parameters were gained: with 10 item cotton stalk,pH 5.0~6.0,temperature 37℃ and fermentation time 9 d,these strains could achieve high glycosylated ratio.