Isolation,Identification,Fermentation Conditions,Enzyme Producing Conditons And Enzymatic Properties Of The Tobacco Straw Degradation Strain YC-2

Crop straw usually refers to the remaining parts of the crops such as rice,beans,rapeseed and corn when harvested.In the south of Anhui province,the main planting pattern is the rotation of tobacco and rice.So the crop straw is a abound resource there.The tobacco straw contains abundant cellulose,which can be biodegraded to be energy sources.Consequently,the research aimed at isolating and screening a efficient strain which can transfer the tobacco straw to energy sources in a short time.For solving the problem of wasting resources and providing good materials for agricultural.At the same time,it can be theoretical and practical basis on environment and sustaintable development in the rotation of tobacco and rice area.There are many kinds of straw degradation bacteria Bacillus spp.,including Bacillus subtilishas,B.brevis,and B.pumilus.They were received widely researched because of their growth rate,extracellular secretion capacity,etc.A tobacco straw degradation strain was isolated fom the rotation of tobacco and rice field in the south of Anhui province,named YC-2.Through physiological and biochemical identification and 16s rDNA,we identified it as Bacillus subtilishas.The YC-2?Bacillus subtilishas?was regarded as the research object in the paper.The factors affecting the growth of microorganism include the quantity of inoculation?the fermentation time?pH?tempeture?medium volume?carbon sources?nitrogen sources and inorganic salt.Fermentation conditions of Bacillus subtilishas YC-2 were optimized by single factor in this paper.The optimum results showed that:2%quantity of inoculatio,the fermentation time was 24h,the original was 6.5,tempeture was 30?,medium volume,80mL/250mL.The optimum medium:2%maltose,2%yeast extract and 0.05%dipotassium hydrogen phosphate.At the same time,we studied the effects of neonicotinoids concentration on the growth of YC-2,the results showed it could be promoted in the lowneonicotinoids concentration like 1?2g/L,while high neonicotinoids would supress the strain.We also explored the degradation of tobacco straw,the strain can degrade 10.14%of the tobacco straw within 7 days while with a rate of 2.26%in the natural condition.Factors affecting the CMCase and FPase activity includes carbon sources,nitrogen sources,temperature,pH,medium volum.and some metal ions.The results showed that:the optional carbon sources was CMC-Na,nitrogen sources was yeast extract,the original was 6.5,tempeture was 35? medium volume,60mL/250mL.Followed the fermentation conditions of Bacillus subtilishas YC-2,we studied the properies of the CMCase and FPase,properies were as follows:the optional temperature was 60?,among 15?-60?,the CMCase and FPase were stable,the optional pH was 7.0,among pH4.0-7.5,the CMCase and FPase were stable.Pb²⁺?Zn²⁺?Na⁺?Fe³⁺?Ni⁺ could strongily inhibit the CMCase and FPase activity while Cr⁺?Cu²⁺?Mn²⁺ also can inhibit them.CMCase and FPase activity could be actived by Co²⁺?Fe²⁺?Mg²⁺?Ca²⁺?Ag⁺.