Ra Chae Hun, Kim Yeong Jin, Lee Sang Yoon, Jeong Gwi-Taek, Kim Sung-Koo
Department of Biotechnology, Pukyong National University, Busan, 608-737, Korea.
Bioprocess Biosyst Eng. 2015 Sep;38(9):1715-22. doi: 10.1007/s00449-015-1411-x. Epub 2015 May 12.
A total monosaccharide concentration of 39.6 g/L, representing 74.0 % conversion of 53.5 g/L total carbohydrate from 80 g dw/L (8 % w/v) Gracilaria verrucosa slurry, was obtained by thermal acid hydrolysis and enzymatic saccharification. G. verrucosa hydrolysate was used as a substrate for ethanol production by 'separate hydrolysis and fermentation' (SHF). The ethanol production and yield (Y EtOH) from Saccharomyces cerevisiae KCCM 1129 with and without adaptation to high galactose concentrations were 18.3 g/L with Y EtOH of 0.46 and 13.4 g/L with Y EtOH of 0.34, respectively. Relationship between galactose adaptation effects and mRNA transcriptional levels were evaluated with GAL gene family, regulator genes of the GAL genetic switch and repressor genes in non-adapted and adapted S. cerevisiae. The development of galactose adaptation for ethanol fermentation of G. verrucosa hydrolysates allowed us to enhance the overall ethanol yields and obtain a comprehensive understanding of the gene expression levels and metabolic pathways involved.
通过热酸水解和酶糖化作用，从80 g干重/L（8% w/v）的江蓠藻浆中获得了39.6 g/L的总单糖浓度，这代表了53.5 g/L总碳水化合物的74.0%转化率。江蓠藻水解产物被用作通过“分步水解和发酵”（SHF）生产乙醇的底物。酿酒酵母KCCM 1129在适应和不适应高半乳糖浓度的情况下，乙醇产量和产率（Y EtOH）分别为18.3 g/L，Y EtOH为0.46，以及13.4 g/L，Y EtOH为0.34。利用GAL基因家族、GAL遗传开关的调节基因以及未适应和适应的酿酒酵母中的阻遏基因，评估了半乳糖适应效应与mRNA转录水平之间的关系。江蓠藻水解产物用于乙醇发酵的半乳糖适应的发展，使我们能够提高整体乙醇产率，并全面了解所涉及的基因表达水平和代谢途径。
