Abstract: The microbial production of ethanol and other solvents from renewable biomass is an attractive alternative to fuels and basic chemical feedstocks. Considerable efforts have been made in the past 10 years to improve the production of altenative fuel chemicals by various biological systems. Much current interest is focussed on the processes based on cellulosic and hemicellulosic feedstocks, the hydrolyzates of which contain a complex mixture of sugars. The technology to convert hexoses to ethanol is well established, however, conversion of pentoses and other sugars poses problems. Filamentous fungi belonging to the genera Fusarium, Monilia and Neurospora have been identified as potential organisms in recent years, that can convert cellulose directly to ethanol. Some species belonging to Fusarium, Mucor and Paecilomyces were also found to efficiently convert xylose to ethanol with high yields. Some fungal strains exhibited relatively higher ethanol and sugar tolerance. However, the major disadvantage with mycelial fungi for ethanol production is the slow bioconversion rate when compared to yeast. Potential bioethanol producing fungal strains, production of extracellular polysaccharases (cellulases and xylanases) and bioconversion of various carbohydrates are reviewed. The factors playing a significant role in determining culture variables and performance in lignocellulosic hydrolysate are discussed.

Abstract: The present invention is directed to a process for the production of vanillin through the bioconversion of a vanillin precursor with a ferulic acid degrading microorganism in the presence of a water soluble sulfhydryl compound and optionally, also in the presence of an assimilable carbon source.

Abstract: SeveralBacillus strains were tested for their ability to hydroxylate oleic acid. Two strains—BD-174 and BD-226—converted oleic acid into a trio of hydroxy-octadecenoic acids. Bioconversion in 72–120 hr produced 5–11% of hydroxy acids relative to oleic acid as measured by gas chromatography. These acids were identified as the 15-, 16- and 17-hydroxy-9-octadecenoic acids by gas chromatography-mass spectrometry of trimethyl silyl derivatives of the product acids and their hydrogenated counterparts.

Abstract: A process for converting cellulosic materials, such as waste paper, into fuels and chemicals utilizing enzymatic hydrolysis of the major constituent of paper, cellulose. A waste paper slurry is contacted by cellulase in an agitated hydrolyzer. The cellulase is produced from a continuous, columnar, fluidized-bed bioreactor utilizing immobilized microorganisms. An attritor and a cellobiase reactor are coupled to the agitated hydrolyzer to improve reaction efficiency. The cellulase is recycled by an adsorption process. The resulting crude sugars are converted to dilute product in a fluidized-bed bioreactor utilizing microorganisms. The dilute product is concentrated and purified by utilizing distillation and/or a biparticle fluidized-bed bioreactor system.

Abstract: Whole cells of Saccharomyces cerevisiae analyzed the conversion of benzaldehyde to benzyl alcohol in aqueous-organic biphasic media. Reaction rate increased dramatically as moisture content of the solvent was increased in the range 0% to 2%. The highest biotransformation rates were observed when hexane was used as organic solvent. Benzaldehyde was also converted to benzyl alcohol by a cell-free crude extract in biphasic systems containing hexane, although the rate of product formation was much lower. Mutant strains of S. cerevisiae lacking some or all of the ADH isoenzymes, ADH I, II, and III, manifested similar rates for bioconversion of benzaldehyde to benzyl alcohol in both aqueous and two-phase systems. In general, conversion rates observed in aqueous media were 2 to 3 times higher than those observed in hexane containing 2% moisture.

Abstract: Aroma compounds production byPenicillium roqueforti spores was studied using hydrolyzed oils as precursors. Lactones possessing a peach odor: 4-dodecanolide, cis-6-dodecen-4-olide, and 4-hexanolide were detected in the bioconversion medium and identified by coupled GC/MS and retention data. Variations were found according to the nature of precursors released from the oils by lipases, the bioconversion time and the nature of the strain.

Abstract: Rising costs for landfill disposal of municipal sewage residues have prompted evaluation of alternative methods for reducing the bulk of the final waste Representative samples of municipal sewage sludge residues were obtained from three major treatment plants in the United States, including Los Angeles (Hyperion), Denver (North Metro), and Chicago (Stickney) The majority of the treated, dewatered sewage sludge solids was found to be volatile (50–60%) and, presumably, biodegradable Additionally, much of the volatile content was solubilized by both acid detergent fiber and neutral detergent fiber treatments, and was presumed to be proteineous microbial biomass in nature Both low- and high-solids anaerobic digester systems, as well as the standard biochemical methane potential (BMP) assay, were utilized to evaluate the anaerobic digestibility of these sewage sludge residues The low methane yields and, thus, the poor organic waste conversion indicated the need for treatment prior to bioconversion The effectivenesss of various pretreatments based on assessment of increased soluble protein or organics and anaerobic digestibility as determined by the BMP assay was evaluated

Abstract: The present invention relates to a process for producing vanillin. Culturing of a basidiomycete fungus of the genus Pycnoporus or of their variants and mutants is performed in a culture medium to which a benzenoid precursor of vanillin has been added, and the vanillin produced by bioconversion of the benzenoid precursor is recovered.

Abstract: WhenActinoplanes strain ATCC 33076, the producer of A-16686 A1, A2 and A3 complex, is fermented in a suitable medium three additional factors, designated A′1, A′2 and A′3 are produced. These were isolated and characterized, and were shown to differ from the parent components of the original complex by lacking one mannose unit. Bioconversion of A factors into A′ factors was achieved by incubation with the mycelium ofActinoplanes ATCC 33076. Factor A′2 has better antibacterial activity than A2 against some bacteria.

Abstract: The bioconversion of D-galacturonic acid to L-ascorbic acid was demonstrated in a new yeast strain isolated from the Japanese Crystal. Both intact cells and a crude mitochondrial extract yielded L-ascorbic acid when D-galacturonic acid was present.

Abstract: Resting cells of a mutant ofArthrobacter sp. (DSM 3747) were used for the bioconversion of D,L-5-benzylhydantoin and related compounds to the corresponding L-amino acids. After optimization of the reaction conditions in shake flask experiments, bioconversions were performed in a preparative scale in a 2-l-bioreactor under nitrogen atmosphere. Specific productivities of 0.4 (p-NO2-L-phenylalanine) up to 3.9 mM amino acid x g cell dry mass−1 x h−1 (p-Cl-L-phenylalanine) were obtained. D,L-5-p-COOH-Benzylhydantoin, D,L-5-phenylhydantoin and D,L-5-p-OH-phenylhydantoin were not accepted as substrates.

Abstract: Study of the bioconversion of primary metabolites to antibiotics can provide a diverse array of novel information. The usual approach is to determine the pathway of carbon during the bioconversion and propose intermediates for further study. However, investigations employing multi-labeled intermediates (e.g., [13C6]glucose) can also provide information on the intermediary metabolism of the producing organism. Moreover, the organism can produce novel (often unrelated) antibiotics or other metabolites of structural interest during the biosynthetic fermentation.

Abstract: An aqueous two-phase system of polyethylene glycol (PEG) and potassium phosphate provided a favorable environment for bioconversion of penicillin G to 6-aminopenicillanic acid (6-APA). The recombinant E. coli cells containing penicillin acylase were partitioned in the phosphate-rich bottom phase, and the product 6-APA in the PEG-rich top phase, which protected the enzyme from deactivation for a longer period of time. The continuous production of 6-APA by recycling the bottom phase showed a slight decrease in enzyme activity from initial 80 mM of 6-APA production to 61 mM during the eight days of operation at a space velocity of 0.12 hours-1. This work showed a possibility that the aqueous two-phase whole-cell enzyme bioconversion could serve as an alternative to immobilized cells on solid matrices.

Abstract: During the last three years most of the research on bioconversion of lignocellulosics has focussed on a process scheme where the substrate is first pretreated, usually by high pressure steam, prior to fractionation into its cellulose, hemicellulose and lignin components. The cellulosic rich fraction is then hydrolyzed enzymatically, followed by fermentation of the liberated sugars to ethanol, while the lignin and pentose sugar rich streams are treated separately. The progress in each of these areas is discussed. Round robin activities between the participating labs were used to provide more uniform methods of quantifying cellulase and xylanase enzyme activities. The various technoeconomic models developed by network members were used to identify probable process schemes and determine technical “bottlenecks”. We could also identify which components of the process were the most cost-intensive and determine the levels at which further increases in yields and productivity would have little effect on the cost of the final product.

Abstract: Animal wastes represent a vast untapped source of energy and nutrients which can be recycled by the use of bioconversion processes. Biomass production, improved digestibility, reductions in environ...

Abstract: Production of L-phenylacetyl carbinol, a precursor of the pharmaceutical L-ephedrine, catalyzed by baker's yeast, was one of the first microbial biotransformation processes to be commercialised. We have studied this biotransformation with whole cells in two-phase systems. Highest biotransformation rates were observed with hexane and hexadecane, having Log P values of 3.5 and 8.8 respectively. Lowest bioconversion rates were observed with toluene and chloroform. The effect of moisture content on biotransformation rate was investigated using hexane as organic phase and a moisture content of 10% was found to be optimal. The effect of organic solvent type on yeast cell structure was investigated. Examination of cells incubated in the two-phase medium for up to 26 h by electron scanning microscopy was performed. Ethylacetate, butylacetate, and chloroform, solvents with relatively low Log P values, exhibited lower biotransformation activities, and appeared to puncture the cells, as shown in electron micrographs. In contrast, cells incubated in media containing hexane and decane appeared quite intact and not distorted. Data are presented on the biotransformation activities observed in the range of aqueous-organic two-phase systems and the effects of solvents on cell structure are illustrated using scanning electron micrographs.

Abstract: The cellulase proteins of Trichoderma reesei: Structure, multiplicity, mode of action and regulation of formation.- Bioconversion of cellulosic materials to ethanol by filamentous fungi.- The enzymes from extreme thermophiles: Bacterial sources, thermostabilities and industrial relevance.- Biosynthesis of storage lipids in plant cell and embryo cultures.- Bioconversions of ergot alkaloids.

Abstract: The production of 2-heptanone from octanoic acid may be performed by free and entrapped spores of Penicillium roquefortii in a water-organic solvent two phase system.An industrial, isoparafflnic solvent, i.e. Hydrosol IP 230 O.S., which may be considered as tetradecane, is well suited for the process. Activities nearly double those achieved with aqueous systems are observed using an initial fatty acid content in the organic layer close to 100 mM and a ratio of the volume of the organic phase to the total volume of the medium of 0.88. The presence of the solvent allows a better recovery of the metabolite by lowering its activity coefficient.Fed-batch experiments performed in an aerated, stirred reactor show that the bioconversion may proceed in the two-phase system for at least 300 h. These conditions allow conversion of 750 mM (108 g · 1-1) fatty acid, and production of 600 mM (68.5 g · 1-1) 2-heptanone.

Abstract: One of the methods commonly used for manufacturing fructose 1,6-diphosphate is based on the enzymatic phosphorylation of glucose with inorganic phosphate using permeabilized brewer's yeast cells. Our results demonstrate that a substantial improvement in the yield of bioconversion can be achieved using fed-batch-grown Saccharomyces cerevisiae cells. Under an appropriate glucose and phosphate to cell ratio the efficiency of bioconversion reaches 70% of the theoretical value.

Abstract: This research project demonstrates the potential for converting the materials present in partially digested sewage sludge to acetic acid for environmental protection purposes, e.g. use in production of calcium magnesium acetate for road deciding salt or scrubbing sulfur dioxide from atmospheric emissions to prevent acid rain problems. Thermal treatment at 121°C for diluted sewage sludge (5:1) in 0.1 N Ca(OH)2 proved to be successful for solubilizing the suspended volatile solids in the digested sewage sludge. The reduction of such solids reached 57% on a dry weight basis. The more soluble sewage sludge could then be treated in a flow-through, low hydraulic retention time, packed column anaerobic reactor to produce acetic acid. The laboratory pilot process first involved suppressing the methane producing bacteria using 0.0005 N bromo ethane sulfonic acid (BES), then feeding the 2.5-1 up-flow anaerobic reactor with thermally conditioned sludge broth in batch and then in continuous feed modes operated at hydraulic retention times of 24, 8 and 4 h. The effluent was monitored for acetic acid production, COD destruction, pH, alkalinity, ammonia, and total nitrogen. Electron scanning microscope photographs were taken to examine the attachment of the acid producing bacteria to the support media. The efficiency of the production of total volatile fatty acids (TVFA) from the treated sewage sludge was 80, 87 and 90% of the theoretical bioconversion possible based on the amount of COD reduced (40–62%). Acetic acid was the major volatile acid form produced.

Abstract: Sugar beet molasses was used as carbon source forSaccharomyces cerevisiae growth and as substrate for bioconversion to fructose diphosphate. The highest level of fructose diphosphate (26.6 g/L) was reached after 10 h incubation of permeabilized cells under appropiate molasses and phosphate to cell ratio and represented a 64% yield of bioconversion.