Germec Mustafa, Kartal Fatma Kubra, Bilgic Merve, Ilgin Merve, Ilhan Eda, Güldali Hazal, Isci Aslı, Turhan Irfan
Dept. of Food Engineering, Akdeniz University, Antalya, 07058, Turkey.
Dept. of Food Engineering, Cankiri Karatekin University, Cankiri, 18100, Turkey.
Biotechnol Prog. 2016 Jul 8;32(4):872-82. doi: 10.1002/btpr.2275. Epub 2016 Apr 27.
The goal of this study was to produce ethanol from rice hull hydrolysates (RHHs) using Pichia stipitis strains and to optimize dilute acid hydrolysis and detoxification processes by response surface methodology (RSM). The optimized conditions were found as 127.14°C, solid:liquid ratio of 1:10.44 (w/v), acid ratio of 2.52% (w/v), and hydrolysis time of 22.01 min. At these conditions, the fermentable sugar concentration was 21.87 g/L. Additionally, the nondetoxified RHH at optimized conditions contained 865.2 mg/L phenolics, 24.06 g/L fermentable sugar, no hydroxymethylfurfural (HMF), 1.62 g/L acetate, 0.36 g/L lactate, 1.89 g/L glucose, and 13.49 g/L fructose + xylose. Furthermore, RHH was detoxified with various methods and the best procedures were found to be neutralization with CaO or charcoal treatment in terms of the reduction of inhibitory compounds as compared to nondetoxified RHH. After detoxification procedures, the content of hydrolysates consisted of 557.2 and 203.1 mg/L phenolics, 19.7 and 21.60 g/L fermentable sugar, no HMF, 0.98 and 1.39 g/L acetate, 0 and 0.04 g/L lactate, 1.13 and 1.03 g/L glucose, and 8.46 and 12.09 g/L fructose + xylose, respectively. Moreover, the base-line mediums (control), and nondetoxified and detoxified hydrolysates were used to produce ethanol by using P. stipitis strains. The highest yields except that of base-line mediums were achieved using neutralization (35.69 and 38.33% by P. stipitis ATCC 58784 and ATCC 58785, respectively) and charcoal (37.55% by P. stipitis ATCC 58785) detoxification methods. Results showed that the rice hull can be utilized as a good feedstock for ethanol production using P. stipitis. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:872-882, 2016.
本研究的目标是使用树干毕赤酵母菌株从稻壳水解物（RHHs）中生产乙醇，并通过响应面法（RSM）优化稀酸水解和解毒过程。优化条件为127.14°C、固液比1:10.44（w/v）、酸比2.52%（w/v）以及水解时间22.01分钟。在这些条件下，可发酵糖浓度为21.87 g/L。此外，优化条件下未解毒的RHH含有865.2 mg/L酚类物质、24.06 g/L可发酵糖、无羟甲基糠醛（HMF）、1.62 g/L乙酸盐、0.36 g/L乳酸盐、1.89 g/L葡萄糖以及13.49 g/L果糖 + 木糖。此外，采用多种方法对RHH进行解毒，与未解毒的RHH相比，发现最佳方法是用CaO中和或木炭处理以减少抑制性化合物。解毒处理后，水解物的含量分别为557.2和203.1 mg/L酚类物质、19.7和21.60 g/L可发酵糖、无HMF、0.98和1.39 g/L乙酸盐、0和0.04 g/L乳酸盐、1.13和1.03 g/L葡萄糖以及8.46和12.09 g/L果糖 + 木糖。此外，使用树干毕赤酵母菌株，以基线培养基（对照）以及未解毒和解毒的水解物来生产乙醇。除基线培养基外，使用中和法（树干毕赤酵母ATCC 58784和ATCC 58785分别为35.69%和38.33%）和木炭解毒法（树干毕赤酵母ATCC 58785为37.55%）获得了最高产量。结果表明，稻壳可作为使用树干毕赤酵母生产乙醇的优质原料来源。© 2016美国化学工程师学会生物技术进展，32:872 - 882，2016。
