Robert W. Detroy

Biomass Conversion: Fermentation Chemicals and Fuels

Recent events clearly establish that petroleum can no longer be relied upon as a stable, economical raw material for energy and industrial chemicals. Plant biomass is currently being evaluated as a desirable alternative raw material to petroleum because of renewability and abundance. The most abundant form of biomass on the planet earth is lignocellulose which is composed of cellulose, hemicellulose, and lignin. An estimated 4 X 10(9) tons per year of cellulose alone is readily available for conversion to energy or feedstuffs. This article explores the current state of research on the transformation of cellulose, hemi-cellulose, and lignin by various microorganisms and the subsequent production of fuels and chemicals. Current research activities are covered including technologies available for the utilization of biomass, chemicals from fermentation processes, conversion of biomass to sugar, direct bioconversion to liquid fuels.

Induction and glucose repression of xylanase from a color variant strain ofAureobasidumpullulans

SummaryXylose, xylobiose and arabinose were identified as natural and direct inducers of xylanase from a color variant strain ofAureobasidiumpullulans. Arabinose, in contrast to xylose, xylobiose and xylan, induced only the major isozyme of xylanase. Xylanase induction was subject to glucose repression.

Direct fermentation of cellodextrins to ethanol byCandida wickerhamii andC. Lusitaniae

SummaryProduction of ethanol from cellodextrins, as large as cellohexose, byCandida lusitaniae andC. wickerhamii was studied.C. lusitaniae fermented only glucose and cellobiose, whereasC. wickerhamii efficiently fermented cellodextrins. Maximum ethanol yields of 29.2 g/liter from 54 g/liter cellodextrins were achieved byC. wickerhamii in 3–4 days.

Alcohol production by mitochondrial mutants and wild type Saccharomyces cerevisiae

SummaryMitochondrial mutants and the wild type strain of Saccharomyces cerevisiae have similar growth, alcohol production rates, and total alcohol production under the same culture conditions.

Stored Bacillus popilliae spores and their infectivity against Popillia japonica larvae

Abstract Bacillus popilliae spores were stored for about 7 years under three separate conditions: frozen in sterile distilled water, smeared on glass microscope slides, and stored in loam soil at room temperature. In separate experiments, each of the 7-year-old preparations was fed to Popilla japonica larvae at concentrations of 10 3 , 10 5 , 10 7 , and 10 9 spores/g of soil. A significant decrease in the percentage of larvae infected occurred in all of the aged spore tests. B. popilliae spores stored in soil, for the extended period, produced 3% larval infection only at the 10 9 spores concentration; similar results were obtained from frozen spores. When P. japonica larvae were fed spores stored dried on slides, about 20% of the larvae developed milky disease. When aged frozen spores were artificially injected into larvae, 12% became infected at concentrations of 1 × 10 6 spores/larvae; dried spores at the same concentration infected about 38% of the insect larvae. We conclude from these data that aged B. popilliae spores are significantly less infective against P. japonica larvae than young spores.

Fermentation of Plant Polysaccharides: Role of Biochemical Genetics

The application of biochemical genetics to the improvement of industrially important microorganisms has long been focused primarily on medical and agricultural products. Over the past few years, several novel ideas for genetic modification have been evoked for microbial systems. These advances in both cellular and molecular genetics and the advent of specific techniques in both in vitro and in vivo gene transfer for prokaryotic and eukaryotic organisms now give rise to applications in biotechnology for conversion of agricultural renewable resources to fuels and chemical feedstocks. These techniques include the use of directed mutasynthesis, cell and protoplast fusion, DNA transformation, and recombinant DNA technology. New and significant advances have been demonstrated in cellulosic conversions, enzymatic hydrolysis, alcohol production and tolerance, and substrate preparation relative to biological conversions. This biotechnology is now a prime candidate for transformation of fermentation genes necessary for plant polysaccharide conversions.