背景:牛磺酸,一种半必需的微量营养素,可以用作某些细菌的硫源;然而,它对发酵产物积累的影响知之甚少。这里,它研究了牛磺酸对真菌生物乙醇和红曲霉氮杂比隆色素(MonAzPs)共同生产的影响。
结果:新分离的真菌与红曲霉具有98.92%的同一性,共同产生23.43g/L的生物乙醇和66.12、78.01和62.37U/mL的红色,黄色和橙色MonAzPs在合成培养基(SM)中连续3天。牛磺酸增强了生物乙醇效价,在玉米秸秆水解产物(CSH)中,乙醇生产率和乙醇产量最大为对照的1.56、1.58和1.60倍,红色,黄色和橙色的MonAzP分别提高了1.24、1.26和1.29倍,分别。牛磺酸对紫癜菌的消耗量极小,对其他两种生物炼制发酵菌株的促进作用并不普遍。牛磺酸增强了糖酵解的基因转录(葡萄糖激酶,磷酸甘油酸变位酶,烯醇化酶和醇脱氢酶)和MonAzPs生物合成(丝氨酸水解酶,C-11-酮还原酶,FAD依赖性单加氧酶,4-O-酰基转移酶,脱乙酰酶,NAD(P)H依赖性氧化酶,FAD依赖性氧化酶,烯酰还原酶和脂肪酸合酶)通过从头RNA-Seq测定。此外,牛磺酸通过显微镜成像分析改变细胞膜结构来改善细胞膜通透性。
结论:牛磺酸通过增加膜的基因转录水平和细胞膜通透性来增强生物乙醇和MonAzP的共同生产。这项工作将提供一种创新,高效和基于牛磺酸的联合生产系统,用于从木质纤维素生物质中大量积累增值生物燃料和生化物质。
BACKGROUND: Taurine, a semi-essential micronutrient, could be utilized as a sulfur source for some bacteria; however, little is known about its effect on the accumulation of fermentation products. Here, it investigated the effect of taurine on co-production of bioethanol and Monascus azaphilone pigments (MonAzPs) for a fungus.
RESULTS: A newly isolated fungus of 98.92% identity with Monascus purpureus co-produced 23.43 g/L bioethanol and 66.12, 78.01 and 62.37 U/mL red, yellow and orange MonAzPs for 3 d in synthetic medium (SM). Taurine enhanced bioethanol titer, ethanol productivity and ethanol yield at the maximum by 1.56, 1.58 and 1.60 times than those of the control in corn stover hydrolysates (CSH), and red, yellow and orange MonAzPs were raised by 1.24, 1.26 and 1.29 times, respectively. Taurine was consumed extremely small quantities for M. purpureus and its promotional effect was not universal for the other two biorefinery fermenting strains. Taurine intensified the gene transcription of glycolysis (glucokinase, phosphoglycerate mutase, enolase and alcohol dehydrogenase) and MonAzPs biosynthesis (serine hydrolases, C-11-ketoreductase, FAD-dependent monooxygenase, 4-O-acyltransferase, deacetylase, NAD(P)H-dependent oxidoredutase, FAD-dependent oxidoredutase, enoyl reductase and fatty acid synthase) through de novo RNA-Seq assays. Furthermore, taurine improved cell membrane permeability through changing cell membrane structure by microscopic imaging assays.
CONCLUSIONS: Taurine reinforced co-production of bioethanol and MonAzPs by increasing gene transcription level and cell membrane permeability for M. purpureus. This work would offer an innovative, efficient and taurine-based co-production system for mass accumulation of the value-added biofuels and biochemicals from lignocellulosic biomass.