水稻秸秆腐解复合菌系RSS-4的选育及其腐解特性

Screening and Functional Properties of a Complex Microbial System RSS-4 for Effective Decomposition of Rice Straws

采用限制性培养技术与温度梯度诱导相结合的方法,从四川成都平原多年还田的土壤中筛选、构建出一组在中温条件下对水稻秸秆具有腐解功能的复合菌系RSS-4。该复合菌系在22℃条件下,稻秆腐解试验表明:pH先升高后降低,最后稳定在7.20;纤维素酶活、半纤维素酶活均经历了先升后降的变化趋势,最高酶活分别为0.91、3.40U;到16d腐解结束时,RSS-4对稻秆、纤维素及半纤维素的降解率分别达到了45.0%、55.5%和44.1%,而木质素在整个腐解过程中未发生明显的变化;说明所筛选构建的这组腐解复合菌系可加速稻秆的腐解。同时发现采用未灭菌的筛选方法筛得的复合菌系RSS-4比灭菌所得的RSS-4′腐解效果要好。

A complex microbial system（CMS） RSS-4 with high ability of rice straw degradation was screened and constructed from the soils sampled from fields cultivated with straw-returning techniques for a long term in Sichuan Province by using the restricted cultivation and gradient-temperature induction methods.When RSS-4-induced rice straws degrading experiment was performed at 22℃,the pH value of the system increased at the initial stage and then slightly decreased until to 7.20.The CMC activity and xylan activity also showed an increase at the beginning and followed by an obvious decrease,with the peak values being 0.91 U and 3.40 U,respectively.At the end of fermentation（16 d）,the weight of rice straws and the component cellulose and hemicellulose reduced to 45.0%,55.5% and 44.0%,respectively,while no obvious change happened in the lignin content.It was also found that the RSS-4 by the unsterilized method has better degradation effect than that of the RSS-4＇ by the sterilized method.