Screening And Application Of Microbial Oil Producing Strains By Xylose Fermentation

In this paper,the microorganism which can make use of xylose to produce microbial oil by self screening was obtained.The fermentation optimization was carried out for the strains with good properties and high oil production rate.The preparation of alternative carbon source and pharmaceutical auxiliary materials were explored.The specific conclusions are as follows:(1)14 microorganisms were obtained from steak spills from cities in Anhui Province through plate initial screening and shaking flask fermentation.The strains were identified by gene sequencing and physiological and biochemical analysis.The comprehensive oil production rate,xylose utilization rate and oil component obtained were high(15.65%),and xylose utilization rate was high(68.56%)The microbial with single component(82.8% linoleic acid)was named as the basket like bacteria gly-3.The following studies were carried out on the microorganism;(2)The best medium composition was determined by single factor experiment.Peptone(high oil production rate)and yeast extract(high biomass),peptone: yeast extract = 1:2(w/w),xylose concentration 15g/l,c/n 150;The optimum fermentation conditions: the amount of liquid loaded is 50ml/250 ml,the fermentation days are 6 days,the p H is 7.0,the temperature is 30 ?,the rotating speed of the shaker is 210 r/min,and the inoculation amount is 6%;Based on the single factor,the best combination of fermentation conditions was obtained by box Behnken center combination design: the filling volume was 55ml/250 ml,the fermentation days were 6 days,the p H was 7.0,the inoculation amount was 6.7%,the optimized oil production rate reached 25.04%,and60.21% higher than that before optimization(15.65%);(3)The best pretreatment technology of sulfur trioxides was found by the best straw pretreatment method.On this basis,the optimal conditions of enzymatic hydrolysis were determined by single factor optimization: 10 g straw straw as substrate,xylanase solution(1.0g/l)added 2ml,The ratio of solid to liquid is 1:10,the temperature of enzymatic hydrolysis is 45 ?,the time of enzymatic hydrolysis is 30 h,and the concentration of xylose in the saccharification solution is 16.06g/l and glucose 1.69g/l;(4)The results of the analysis of acid value,saponification value,iodine value and peroxide value of the oil obtained by using enzymatic glycosylation solution as the substitute carbon source of the fermentation of basket bacteria gly-3 were carried out.The results met the requirements of Pharmacopoeia of the people's Republic of China with monolinoleic glyceride as auxiliary materials,which provided a new idea for the following research on the medicine of the oil.