蜡质降解微生物的筛选、表征及其秸秆降解作用

Screening, Characterization and Straw Degradation of Wax Degradation Microorganism

摘要: 我国秸秆资源丰富，但其降解速率慢，仍缺乏高效降解菌剂，表面蜡质层破坏是秸秆降解的第一步。本文从林下腐殖土、腐根等材料中筛选蜡质降解菌，分析菌株对叶表蜡质层的破坏作用，并对其秸秆降解作用进行研究。最终筛选出一种降解蜡质效果较好的菌株(L1-1)，核酸分类学鉴定该菌株为金黄杆菌(Chryseobacterium)。菌株L1-1的蜡质相对降解率为39%，对叶表面具有较强的破坏作用。单一菌种降解秸秆的能力有限，蜡质降解菌与木质素降解菌或纤维素降解菌组合可提高秸秆降解率，木质素与纤维素降解菌组合相对降解率可达30.4%。本研究结果表明，在秸秆降解中宜采用复合菌群，蜡质降解菌株在其中可能起到先导作用，木质素降解菌与纤维素降解菌共同使用秸秆降解效果较好。

Abstract: Straw resources is rich in China, and for the lower degrading rate, the degradation of straw is lack of the efficient degrading bacteria. The destruction of surface waxy is the first step in the degradation of straw. In this paper, wax-degrading bacteria were screened from understory, humus soil, rotten root and other materials, and their damage to the waxy layer of leaf surface was analyzed. At last, the straw degradation of waxy-degrading strain was determined. Experimental results were as fol-lows: the strain (L1-1) with the higher wax degradation rate was screened, which was identified as Chryseobacterium sp. by nucleic acid taxonomy technology. The relative wax-degrading rate of L1-1 is about 39%. And the waxy layer on the surface leaf could be disrupted distinctly by L1-1. The straw-degrading ability of L1-1 is limited, while combined with lignin-degrading or cellulose-degrading bacteria could increase degradation rate. And the relative degradation rate of multibacterial species of lignin-degrading combined with cellulose-degrading bacteria was 30.36%. The results indicated that, compound strains should be used in the degradation of straw, and wax-degrading strains might play a leading role in this process. The straw degradation was outstanding when lignin-degrading combined with cellulose-degrading strains.