Isolation, identification and corn stalk degradation charac-teristics of cellulose-degrading bacterial strain NH11

Abstract:

[Objective] This study is aimed to obtain effective cellulose-degrading bacterial strains and study the characteristics of cellulase production and degradation characteristics used NH3?H2O pretreated corn stalk as substrate, and explore mechanism of cellulose enzyme so as to improve the resource utilization rate of agricultural solid wastes. [Methods] LB medium was used to obtain eleven bacterial strains (NH1?11) from earthworm farm. CMC-Na was used in preliminary medium and congo red staining method to screening strains. Influence of pretreatment to cellulose production ability of NH11 and degradation rate of substrates was studied. Morphological characteristics of NH11 was observed by electron microscope and identified by 16S rRNA and Biolog method. [Results] Bacterial strain NH11 was isolated and identified as Bacillus subtilis. The maximum degradation rate of untreated and pretreated corn stalk was 14.24% and 24.73% when culture temperature was 30 °C after five days. CMC cel-lulose activity of NH11 reached to 153.84 U/mL and FPA cellulose activity to 197.24 U/mL in treatment group, 11.45% and 10.59% higher than untreated group. [Conclusion] NH11 has a high cellulase productivity, and NH3?H2O pretreatment could enhance the degradation rate of corn stalk. NH11 has a high value in straw compost, mushroom culture medium and ruminant feed production.