【摘要】 为了研究一株蜡样芽孢杆菌(Bacillussp.X10-1-2)对稻草的降解作用,测定了发酵过程中发酵液的纤维素酶和半纤维素酶活、可溶性总糖和还原糖浓度以及底物残渣重、残渣结晶度、傅立叶红外光谱和表面结构的变化.发现在发酵过程中蜡样芽孢杆菌菌体产酶的过程也就是木质纤维素的降解糖化过程.上清液中的纤维素酶活和半纤维素酶活分别在发酵进行到第8 h和20 h时达到最高峰.总糖含量于4 h达到最高值,然后下降到一定程度后保持恒定.还原糖含量随发酵进行不断下降,达到一定值后保持恒定.该菌株对稻草长达5 d的降解过程中结晶度变化十分显著,第3 d时达到最高峰,而后又迅速下降.此菌株对稻草中各组分都有一定降解,其中纤维素、半纤维素和木质素的降解率分别为3.35%、0.91%和2.81%.该菌株主要降解稻草的薄壁细胞,使薄壁细胞发生严重皱缩.这预示,该菌株在造纸工业具有良好的应用前景.更多还原

【Abstract】 In order to study the degradation of straw by Bacillus cereus(Bacillus sp.X10-1-2),the concentration of reducing sugar and soluble total sugar,activities of cellulase and hemicellulase in fermented broth,the weight loss,crystallinity,FT-IR and surface structure of residue were measured.The results show that the process of biodegradation of lignocellulose is actually the simultaneous saccharification and fermentation.Cellulase and hemi-cellulase activities reached the highest level in fermentation for 8 h and 20 h,respectively.Concentration of soluble total sugar reached the highest level in 4 h,then decreased with time and kept invariable at a certain value.Meanwhile,concentration of reducing sugar decreased with fermentation and then maintained an invariable value.Crystallinity of residue was obviously changed after the cultivation for 5 d.It reached the highest level in 3 d and then decreased rapidly.FT-IR spectrum of residue showed that Bacillus sp.X10-1-2 degraded cellulose,hemi-cellulose and lignin in straw to some tent.After cultivation for 5 d,the degradation ratio of cellulose,hemicellulose and lignin in straw were 3.35%,0.91% and 2.81%,respectively.SEM of surface structure of the straw degraded by Bacillus sp.X10-1-2 showed that the thin-walled cell of straw became wrinkled and wizen.The study predicts a good application of this strain in the field of pulp and paper industry.更多还原