Michael A. Cotta

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Rice hulls, a complex lignocellulosic material with high lignin (15.38 +/- 0.2%) and ash (18.71 +/- 0.01%) content, contain 35.62 +/- 0.12% cellulose and 11.96 +/- 0.73% hemicellulose and has the potential to serve as a low-cost feedstock for production of ethanol. Dilute H2SO4 pretreatments at varied temperature (120-190 degrees C) and enzymatic(More)
The lack of industrially suitable microorganisms for converting biomass into fuel ethanol has traditionally been cited as a major technical roadblock to developing a bioethanol industry. In the last two decades, numerous microorganisms have been engineered to selectively produce ethanol. Lignocellulosic biomass contains complex carbohydrates that(More)
Fermentation of sulfuric acid treated corn fiber hydrolysate (SACFH) inhibited cell growth and butanol production (1.7+/-0.2g/L acetone butanol ethanol or ABE) by Clostridium beijerinckii BA101. Treatment of SACFH with XAD-4 resin removed some of the inhibitors resulting in the production of 9.3+/-0.5 g/L ABE and a yield of 0.39+/-0.015. Fermentation of(More)
Storage of swine manure is associated with the microbiological production of a variety of odorous chemicals including ammonia, organic acids and alcohols, and sulphides. Although largely the product of microbiological activity, little is known about the microorganisms present in swine manure. In order to gain a better understanding of the types and(More)
Wheat straw used in this study contained 44.24 +/- 0.28% cellulose and 25.23 +/- 0.11% hemicellulose. Alkaline H(2)O(2) pretreatment and enzymatic saccharification were evaluated for conversion of wheat straw cellulose and hemicellulose to fermentable sugars. The maximum yield of monomeric sugars from wheat straw (8.6%, w/v) by alkaline peroxide(More)
Lignin is known to impede conversion of lignocellulose into ethanol. In this study, forage sorghum plants carrying brown midrib (bmr) mutations, which reduce lignin contents, were evaluated as bioenergy feedstocks. The near-isogenic lines evaluated were: wild type, bmr-6, bmr-12, and bmr-6 bmr-12 double mutant. The bmr-6 and bmr-12 mutations were equally(More)
Beta-D-xylosidase from the ruminal anaerobic bacterium, Selenomonas ruminantium (SXA), catalyzes hydrolysis of beta-1,4-xylooligosacharides and has potential utility in saccharification processes. The enzyme, heterologously produced in Escherichia coli and purified to homogeneity, has an isoelectric point of approx 4.4, an intact N terminus, and a Stokes(More)
In these studies, butanol (acetone butanol ethanol or ABE) was produced from wheat straw hydrolysate (WSH) in batch cultures using Clostridium beijerinckii P260. In control fermentation 48.9 g L(-1) glucose (initial sugar 62.0 g L(-1)) was used to produce 20.1 g L(-1) ABE with a productivity and yield of 0.28 g L(-1 )h(-1) and 0.41, respectively. In a(More)
Saccharomyces’ physiology and fermentation-related properties vary broadly among industrial strains used to ferment glucose. How genetic background affects xylose metabolism in recombinant Saccharomyces strains has not been adequately explored. In this study, six industrial strains of varied genetic background were engineered to ferment xylose by stable(More)
Dried distillers' grains with solubles (DDGS), a co-product of corn ethanol production, was investigated as a feedstock for additional ethanol production. DDGS was pretreated with liquid hot-water (LHW) and ammonia fiber explosion (AFEX) processes. Cellulose was readily converted to glucose from both LHW and AFEX treated DDGS using a mixture of commercial(More)