ORP对酿酒酵母在木质纤维素水解液抑制物中发酵的影响

摘要

A broad range of inhibitors in hydrolysate of lignocellulose, including weak acids, furan derivatives and phenolic compounds restrain yeast growth and subsequent fermentation. The effect of oxido-reduction potential (ORP) regulation on yeast cell tolerance to the presence of acetic acid, furfural and phenol was investigated. Cell growth and metabolite distribution changed under different ORP levels [(305±5) mV, (157±8) mV and (−150±5) mV] by feeding oxidant (potassium ferricyanide, K3[Fe(CN)6]) and reductant (dithiotreitol, DTT). Compared to the control group, cell growth was enhanced, and ethanol yield increased except for phenol group. The yield of glycerol was enhanced under both oxidizing and reducing conditions, since glycerol was a main protective molecule in yeast. High ORP level facilitated detoxification of inhibitors thanks to high biomass accumulation.%木质纤维素水解液中的毒性副产物对酿酒细胞具有抑制作用，采用氧化还原电位(oxidoreduction potential, ORP)调控，能够提高细胞对抑制物的耐受性。考察了代表性抑制物乙酸、糠醛及苯酚对酵母细胞生长和代谢的影响，并通过添加氧化剂赤血盐(K3[Fe(CN)6])和还原剂二硫苏糖醇(DTT)调节发酵液ORP初始值在（305±5）mV、（157±8）mV及（−150±5）mV，研究不同ORP条件下细胞对抑制物的耐受性影响。结果表明，氧化态能提高生物量并缩短发酵时间。除苯酚外，氧化态也利于提高乙醇的收率。对细胞保护剂甘油合成的方面，氧化态和还原态都会促进甘油合成。在水解液脱毒方面，氧化态表现比还原态要好，因为氧化态促进生物量积累，有利于通过细胞自身代谢脱毒。