利用薯类淀粉生产酵母单细胞蛋白

Single cell protein production from sweet pota-to starch by yeast

研究目的筛选能直接利用薯类淀粉的酵母,并研究其最适发酵条件。研究背景我国南北盛产薯类作物,这些高产作物主要成份是淀粉,含量达65％左右,但蛋白质甚少(1～3％),并不是理想的食物和动物饲料。如果通过淀粉分解酵母将其转化为单细胞蛋白,可大大提高其蛋白质含量。研究方法采集土样在固体培养基上分离,将获得的酵母菌株发酵培养,收集菌体并测定菌体干重和蛋白质含量。研究结果筛选出saccharomyces mf—3和schwaniomvces tf-6两株具有淀粉分解能力的优良菌株,其最适发酵条件为:淀粉浓度4％,起始pH值5.5;起始硫酸铵和尿素(1:1)加入量为0.2％,6小时和10小时后分别加0.2％和0.1％;30℃条件下发酵14小时。最终可获干酵母分别为21g/L和22g/L,且蛋白质含量在47％以上,生物转化率达50％。结论获得的干酵母无毒、营养丰富,是理想的食物和动物饲料。

Objective To isolate the yeast of utilizingsweet potato starch directly and study its optimumfermentation conditions . Background The main component of thesweet potato is starch(starch content is 65％).Soit I‘S nol the best food and animal feed.Single cellprotein(SCP)production from the sweet potatostarch by amylolytic yeast may increase its proteincontent. Methods The soil【samples.collected is I‘SO一 ● ●lated in the solid culture.The amylolytic yeast ob-tained is fermented.After the yeast is collected,yield and protein content of the yeast is analysed. Results The better strains of anaylolyticyeast.saccharom.vces现卜3 and schwaniomycestf-6 are isolated.Its opu‘mum fermentation.con-ditions are as follows:4％sweet potato starch;ini—tial pH 5.5;initially adding 0.2％(NH4)2S04 andurea(1:1)respectively;temperature 30~C;fermen-tation time 14 hour.the yield of dry yeast are 2 1 g/L and 22g/L resPectively.The protein con-tent of the yeast is more than 47％.A recovery of50％(O.5g of dried biomass from lg of starch)is obtained. Conclusion The single cell protein product obtained is non—toxic and ntritional、value is high.So it would be a favorable food and animal feed