Authors: Rajat Sharma Buddhi P Lamsal William J Colonna
Publish Date: 2015/11/21
Volume: 39, Issue: 1, Pages: 105-113
Abstract
Pretreatment of six fibrous biomasses switchgrass alfalfa soy hulls soy fiber DDGS and Baggase and subsequent hydrolysis using cellulolytic enzymes at a 25 v/v and 5 v/v loading 25 v/v and 5 v/v loading was compared for higher amounts of sugars released Soaking of biomasses of switchgrass alfalfa soy hulls and bagasse in 15 w/w ammonia was optimal at 60 °C for 12 h followed by enzymatic hydrolysis yielding 72 70 80 and 75 carbohydrate conversions respectively However soaking in ammonia was not needed for soy fiber and DDGS as these contained very little lignin Ultrasonication for 3 min 100 amplitude 170 µM was found to be optimal for soy fiber and DDGS from which 77 and 83 carbohydrate conversion respectively was obtained following enzyme treatment at 5 w/v enzyme The sugars released by enzymatic hydrolysis of pretreated biomass were utilized as an energy source by Bacillus subtilis in fermentation media at 2 w/v of concentration In shake flask trials cell growth was 15–20 higher on hydrolysates of ammoniatreated switchgrass and alfalfa vs glucosebased control media due to the presence of a wider range of monomeric sugars glucose xylose arabinose mannose and galactose In contrast growth was less on soy hull hydrolysates prepared with ammonia pretreatment
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