Abstract: Several mutated strains of Scheffersomyces stipitis are generated by repetitive culturing of the parent strain on two types of concentrated hydrolyzates and with ethanol-challenged xylose-fed continuous culture. Isolates collected from various enriched populations are screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation is used to identify those isolates with best performance across diverse conditions.

Abstract: The present invention provides for the use of oleaginous yeast strains that are capable of converting lignocellulosic hydrolysates to lipids. More specifically, under specific molar carbon to nitrogen ratios of treated biomass hydrolysates, oleaginous yeasts are able to accumulate lipids that are suitable for the manufacture of biofuels and other products of interest. Additionally, some yeast species provided herein produce carotenoids when grown utilizing the disclosed methodologies.

Abstract: Several mutated strains of Scheffersomyces stipitis are generated by repetitive culturing of the parent strain on two types of concentrated hydrolyzates and with ethanol-challenged xylose-fed continuous culture. Isolates collected from various enriched populations are screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation is used to identify those isolates with best performance across diverse conditions.

Abstract: Several mutated strains of Scheffersomyces stipitis are generated by repetitive culturing of the parent strain on two types of concentrated hydrolyzates and with ethanol-challenged xylose-fed continuous culture. Isolates collected from various enriched populations are screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation is used to identify those isolates with best performance across diverse conditions.

Abstract: A xylose isomerase (XI) enzyme which exhibits increased activity and affinity for xylose is produced by strain TC2-24 of the rumen bacterium, Prevotella ruminicola. The gene encoding this enzyme may be used to produce improved recombinant yeast capable of utilizing xylose. The recombinant yeast are preferably transformed with heterologous polynucleotide sequences coding both the P. ruminicola XI, and the xylulokinase (XKS) of a Prevotella species. Yeast transformed with the polynucleotide sequences coding both of these XI and XKS exhibit significantly increased xylose utilization and cell growth on a culture medium containing xylose as the sole carbon source, in comparison to yeast transformed with XKS and XI from other sources.

Abstract: Agricultural biomass hydrolysate is detoxified by culturing in the presence of the fungus Coniochaeta ligniaria (teleomorph) or its Lecythophora (anamorph) state. This organism is capable of significantly depleting the toxicant levels of furans, particularly furfural and 5-hydroxymethylfurfural. A new strain of the fungus has been isolated and deposited in the Agricultural Research Culture Collection (NRRL) in Peoria, Ill., as Accession No. NRRL 30616. The detoxified agricultural biomass hydrolysate is useful as a substrate for industrial fermentation processes, especially in saccharification treatments for bioethanol production.

Abstract: Recombinant bacteria are disclosed which are transformed with heterologous DNA coding for alcohol dehydrogenase (adh) and pyruvate decarboxylase (pdc), and which are effective for use in the production of ethanol, but which do not require the presence of antibiotics in the culture medium to maintain genetic stability and high ethanol productivity. These recombinant bacteria are produced using mutant host strains which are substantially deficient in the ability to fermentatively reduce pyruvate. When grown in an anaerobic environment, the recombinant pyruvate mutants transformed with the adh and pdc genes are genetically stable, maintaining the inserted genes and ethanol productivity even in the absence of antibiotics.