Published in Scientific Bulletin. Series F. Biotechnologies, Vol. XX
Written by Mustafa GERMEC, Irfan TURHAN, Ercan YATMAZ, Nedim TETIK, Mustafa KARHAN
Value-added products such as biofuels, enzymes, polysaccharides, pharmaceuticals, and organic acids can be produced from renewable resources such as carob pods, wheat straw, rice straw, rice husk, sugarcane bagasse, etc. by fermentation. Tea processing waste (TPW) is one of the renewable resources, which contains 13.60% cellulose, 32.16% hemicellulose, and 33.38% lignin. Due to its high carbohydrate content (total 45.76% wt), TPW can be used for production of value-added products. Therefore, the main objectives of this study were undertaken not only to determine the chemical composition of acid-pretreated tea processing waste hydrolysate (APTPWH) but also to investigate the effect of pH, inoculum size, agitation, and nitrogen sources on ethanol production from APTPWH without detoxification by using Saccharomyces cerevisiae in a stirred tank bioreactor. Results showed that it contains no HMF and lactic acid, 16.03 g/L fermentable sugar (FS), 0.43 g/L acetic acid, 2.61 g/L glucose, 4.14 g/L fructose+xylose, and 2.27 g/L phenolics. For batch ethanol fermentations, optimum conditions were found to be pH controlled at 5.5, 5% inoculum size (v/v), 150 rpm agitation speed, and yeast extract, which achieved as 25.55% yield (YP/S), 1.75 g/L ethanol production (P), and 0.38 g/L/h productivity (QP). Consequently, ethanol could be relatively produced from TPW without detoxification.
[Read full article] [Citation]
