含乙酸玉米芯水解液中四株油脂酵母联产多糖与油脂的研究

Production of Polysaccharides and Lipids by Four Oleaginous Yeasts in Corncob Hydrolysate with Acetic Acid

摘要:

为了研究木质纤维素水解液中高浓度乙酸的存在对油脂酵母发酵的影响，本研究以4株油脂酵母（皮状丝孢酵母、浅白隐球酵母、Trichosporon dermatis与Trichosporon coremiiforme）为研究对象，在玉米芯水解液中添加高浓度乙酸（15 g/L）作为发酵底物，研究发酵的底物代谢与产物积累规律。结果表明：发酵培养基中的糖与乙酸几乎可被皮状丝孢酵母与T. dermatis完全代谢；而T. coremiiforme与浅白隐球酵母对糖与有机酸的代谢效果不佳。皮状丝孢酵母与T. dermatis在高效降低高底物浓度培养基的COD的同时，可在胞外合成一定浓度的多糖产品。四株油脂酵母的油脂脂肪酸组成以C16、C18系列为主，其中油酸（C18:1）比例最高；除合成微生物油脂外，它们还能在胞内大量积累多糖类物质以及少量的蛋白质与灰分。本文可为油脂酵母利用廉价原料联产酵母多糖与微生物油脂这两种高附加值食品提供参考。

Abstract:

In order to study the influence of high-concentration acetic acid in lignocellulosic hydrolysates on fermentation by oleaginous yeast, four oleaginous yeasts (Trichosporon cutaneum, Cryptococcus albidus, Trichosporon dermatis, and Trichosporon coremiiforme) were chosenand corncob hydrolysate with the addition of high-concentration acetic acid was used as the fermentation substrate to explore patterns in substrate metabolism and product accumulation during fermentation.Sugars and acetic acid in the fermentation media could be almost completely metabolized by T. cutaneum and T. dermatis, but T. coremiiforme and C. albidus showed little metabolism effect on sugars and organic acids. Besides efficiently reducing the chemical oxygen demand (COD) of the medium with high substrate concentration, T. cutaneum and T. dermatis synthesized a certain concentration of extracellular polysaccharide products. The fatty acids of the four oleaginous yeasts were mainly composed of C16 and C18 series, and the proportion of oleic acid (C18:1) was the highest; in addition to microbial oil, they also accumulated a large amount of polysaccharide and a small amount of protein and ash. This study provides a reference for the production of yeast polysaccharide and microbial oil from low-cost raw materials using oleaginous yeasts.