Fermentation of Barley by Using Saccharomyces cerevisiae : Examination of Barley as a Feedstock for Bioethanol Production and Value-Added Products

Abstract

The objective of this study was to examine the ethanol yield potential of three barley varieties (Xena, Bold, and Fibar) in comparison to two benchmarks, corn and wheat. Very high gravity (VHG; 30% solids) fermentations using both conventional and Stargen 001 enzymes for starch hydrolysis were carried out as simultaneous saccharification and fermentation. The grains and their corresponding dried distiller's grain with solubles (DDGS) were also analyzed for nutritional and value-added characteristics. A VHG traditional fermentation approach utilizing jet-cooking fermentation revealed that both dehulled Bold and Xena barley produced ethanol concentrations higher than that produced by wheat (12.3, 12.2, and 11.9%, respectively) but lower than that produced by corn (13.8%). VHG-modified Stargen-based fermentation of dehulled Bold barley demonstrated comparable performance (14.3% ethanol) relative to that of corn (14.5%) and wheat (13.3%). Several important components were found to survive fermentation and were concentrated in DDGS. The highest yield of phenolics was detected in the DDGS (modified Stargen 001, 20% solids) of Xena (14.6 mg of gallic acid/g) and Bold (15.0 mg of gallic acid/g) when the hull was not removed before fermentation. The highest concentration of sterols in DDGS from barley was found in Xena (3.9 mg/g) when the hull was included. The DDGS recovered from corn had the highest concentration of fatty acids (72.6 and 77.5 mg/g). The DDGS recovered from VHG jet-cooking fermentations of Fibar, dehulled Bold, and corn demonstrated similar levels of tocopherols and tocotrienols. Corn DDGS was highest in crude fat but was lowest in crude protein and in vitro energy digestibility. Wheat DDGS was highest in crude protein content, similar to previous studies. The barley DDGS was the highest in in vitro energy digestibility.

Production of multiple extracellular enzyme activities by novel submerged culture of Aspergillus kawachii for ethanol production from raw cassava flour

“…FAN production rates for the crude barley-grown A. kawachii FS005 culture broth, the milled crude barley-grown A. kawachii FS005 culture broth and STARGEN™ 001 were 118.7, 48.6, and 58.1 mg/l/h, respectively. Recently, the addition of acid protease from A. niger was found to have a synergistic eVect on the hydrolysis of various starch substrates including corn and barley under STARGEN-based enzymatic sacchariWcation conditions [5,25]. It is likely that the lower acid protease and acid carboxypeptidase activities in the milled crude barley-grown A. kawachii FS005 culture broth contributed to the ineYcient hydrolysis of the raw cassava Xour.…”

Effect of Distiller's Dried Grains with Solubles (DDGS) Feeding to Dairy Cows on Oxidative Status under Hot Condition

“…DDGS are low in lignin and starch and high in digestible neutral detergent fiber 3), 11) compared with original corn grains. Besides, the DDGS contain higher protein and fat, which is rich in vitamin E with some variation in the production process 4) . Vitamin E, as an oil-soluble vitamin, is considered effective to reduce the oxidative stress of dairy cows in hot conditions.…”

Industrial Enzyme Applications in Biorefineries for Starchy Materials

“…Most ethanol producers follow the conventional process for conversion of grain starches into fermentable sugars and ethanol (Suresh et al 1999 ;Gibreel et al 2009 ;Nikolić et al 2010 ;Linko et al 1983 ). The conventional process consists of either of a four-step process with milling (wet or dry), liquefaction, saccharifi cation, and fermentation ( Fig.…”