Abstract: In the one-step conversion of wood into lactic acid by Simultaneous Saccharification and Fermentation (SSF), inhibition effects caused by hydrolysis- and fermentation-derived compounds on both enzymatic activity and fermentative ability of microorganisms appear when the operation is carried out under conditions leading to high productivities. The main effects inhibiting SSF have been assessed, and the results obtained in fed-batch experiments allowed the definition of strategies for improving the overall bioconversion process. As cellobiose caused significant inhibition of cellulases, the supplementation of media with β-glucosidase resulted in improved kinetics and yields. The inhibition of both enzymatic activity and microbial metabolism by lactic acid was confirmed. Intermittent removal of lactic acid by passing the fermentation media through an anion-exchange resin column resulted in increased productivities and yields. Improved conversion of pretreated wood into lactic acid (67% conversion of cellulose into lactic acid, with maximum lactic acid concentration of 108 g dm−3 and a productivity of 0.94 g dm−3 h−1) was achieved combining multiple substrate addition, supplementation with fresh nutrients and enzymes and removal of lactic acid. © 2001 Society of Chemical Industry

Abstract: The use of purified xylan as a substrate for bioconversion into xyianases increases the cost of enzyme production. Consequently, there have been attempts to develop a bioprocess to produce such enzymes using different lignocellulosic residues. Filamentous fungi have been widely used to produce hydrolytic enzymes for industrial applications, including xyianases, whose levels in fungi are generally much higher than those in yeast and bacteria. Considering the industrial importance of xyianases, the present study evaluated the use of milled sugarcane bagasse, without any pretreat-ment, as a carbon source. Also, the effect of different nitrogen sources and the C:N ratio on xylanase production by Aspergillus awamori were investigated, in experiments carried out in solid-state fermentation. High extracellular xylanolytic activity was observed on cultivation of A. awamori on milled sugarcane bagasse and organic nitrogen sources (45 IU/mL for endoxylanase and 3.5 IU/mL for β-xylosidase). Endoxylanase and β-xylosidase activities were higher when sodium nitrate was used as the nitrogen source, when compared with peptone, urea, and ammonium sulfate at the optimized C:N ratio of 10:1. The use of yeast extract as a supplement to the these nitrogen sources resulted in considerable improvement in the production of xyianases, showing the importance of this organic nitrogen source on A. awamori metabolism.

Abstract: The biotransformation of (S)-(+)-linalool by different Aspergillus niger strains was studied, using submerged shaken liquid cultures. One strain, A. niger DSM 821, was able to convert the substrate to cis- and trans-furanoid linalool oxide (yield 30% and 5%, respectively) and cis- and trans-pyranoid linalool oxide (yield 14% and 1.5%, respectively). The main metabolites, cis-(2S,5R)-furanoid and cis-(3S,6S)-pyranoid linalool oxide, have a sweet, floral, creamy odor and are used in perfumery. The culture conditions involved, such as the composition of the broth and the type and concentration of cosolvent applied and possible adaptation to the substrate during inoculation, were investigated. It was found that (S)-(+)-linalool was converted much better than (R)-(-)-linalool and that no significant chemical conversion of the substrate occurred in control flasks at pH 3.5. Three cosolvents for improving the solubility of linalool in the culture broths were compared, namely MeOH, EtOH, and acetone. The highest bioconversion yields were obtained when the substrate was applied as a diluted solution in acetone. Screening of the fungi for their biotransformation capacity was performed by solid-phase microextraction.

Abstract: The present invention is directed to a substantially odorless biological treatment process for converting solid and liquid organic wastes into a beneficial humus material comprising: combining organic waste with a liquid thereby creating a waste stream; treating said waste stream in an aqueous environment containing about 1015 or more biological microorganisms with an average doubling time of less time than about 30 days; maintaining less than about 2.0mg/1 of dissolved oxygen in said aqueous environment; and separating solids from said aqueous environment for the recovery of an organic humus material. The present invention also provides for a novel nutrient rich humus material produced from the biological treatment process. The bioconversion process of the present invention results from low oxygen concentrations and high quantities of microorganisms in a diverse microbial community.

Abstract: This study was conducted to evaluate the effect of an eminent decay fungus, Phanerocheate chrysosporium of organic residues on wastewater sludge for its improvement through decomposition and separation of waste particles by Liquid State Bioconversion (LSB). The effect of fungal treatment was compared to uninoculated (Control) at three different harvests 7, 14 and 21 days after inoculation (DAI). The observed results showed that the weight loss and solid content of wastewater sludge were significantly influenced by Phanerocheate chrysosporium. Both parameters were highly influenced at 7 DAI. The COD and pH of wastewater sludge were also highly influenced by fungal treatment.

Abstract: Optimization of whole-cell bioconversion of the polycyclic aromatic hydrocarbons (PAHs) anthracene, phenanthrene, and naphthalene to the enantiomerically pure corresponding cis-dihydroxydihydro derivatives by the Escherichia coli JM109 (pPS1778) recombinant strain, carrying the naphthalene dioxygenase and corresponding regulatory genes cloned from Pseudomonas fluorescens N3, in micellar systems, is presented. We show that direct microemulsion systems, where a nonionic surfactant such as 1.5% (v/v) Triton X-100 plus 0.6% to 1.0% (v/v) selected oils are able to solubilize the PAHs tested at relatively high concentrations (initial concentrations in the reaction medium ≥10 mM for naphthalene and phenanthrene and ≥2 mM for anthracene), and allow for more efficient substrate bioconversion. These media, while not affecting bacteria viability and performance, provide increased efficiency and final product yields (100% for naphthalene, >30% for anthracene, >60% for phenanthrene). The phase behavior of the direct microemulsion systems for the different substrates and oils utilized was monitored as a function of their volume fraction by light scattering experiments, and related to the bioconversion results. For anthracene and phenanthrene, the dihydroxylated products have an inhibitory effect on the conversion reactions, thus hindering complete turnover of the substrates. We ascertain that such inhibition is reversible because removal of the products formed allowed the process to start over at rates comparable to initial rates. To allow for complete conversion of the PAHs tested a stepwise or continuous separation of the product formed from the micellar reaction environment is being developed. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 240–248, 2001.

Abstract: H. MALAOUI AND R. MARCZAK. 2001. Aims: Clostridium butyricum E5 wild-type and mutant E5-MD were cultivated in chemostat culture on glycerol in order to compare the properties of two key enzymes of glycerol catabolism, i.e. propanediol and glycerol dehydrogenase. Methods and Results: These two enzymes, which belong to the dha regulon, were separated by gel filtration. Both dehydrogenase activities displayed similar properties, such as pH optimum values, specificity towards physiological substrates and dependence on Mn2+. Both strains accumulate glycerol at high levels. Conclusion: The mutant D strain contained a propanediol dehydrogenase activity which had a low affinity for its physiological substrate, leading to the conclusion that this strain would seem more resistant to the toxic effect of 3-hydroxypropionaldehyde than the wild-type. Significance and Impacts of the study: These properties make Cl. butyricum mutant D strain the best candidate so far to be used as a biotechnological agent for the bioconversion of glycerol to 1,3-propanediol.

Abstract: We have applied the methodology of metabolic engineering in the investigation of the enzymatic bioreaction network in Rhodococcus sp. that catalyzes the bioconversion of indene to (2R)-indandiol suitable for the synthesis of cis-1-amino-2-indanol, a precursor of the HIV protease inhibitor, Crixivan. A chemostat with a novel indene air delivery system was developed to facilitate the study of steady state physiology of Rhodococcus sp. I24. Prolonged cultivation of this organism in a continuous flow system led to the evolution of a mutant strain, designated KY1, with improved bioconversion properties, in particular a twofold increase in yield of (2R)-indandiol relative to I24. Induction studies with both strains indicated that KY1 lacked a toluene-inducible dioxygenase activity present in I24 and responsible for the formation of undesired byproducts. Flux analysis of indene bioconversion in KY1 performed using steady state metabolite balancing and labeling with [14C]-tracers revealed that at least 94% of the indene is oxidized by a monooxygenase to indan oxide that is subsequently hydrolyzed to trans-(1R,2R)-indandiol and cis-(1S,2R)-indandiol. This analysis identified several targets in KY1 for increasing (2R)-indandiol product yield. Most promising among them is the selective hydrolysis of indan oxide to trans-(1R,2R)-indandiol through expression of an epoxide hydrolase or modification of culture conditions.

Abstract: This paper describes the bioconversion of 2-methyl-1,3-propanediol to (R)-beta-hydoxyisobutyric acid (HIBA) by Acetobacter ALEI in a hollow fiber membrane bioreaction system arrangement that allows the integration of three liquid phases: the aqueous bioconversion phase, the organic phase consisting of a solution of trioctyl phosphine oxide (TOPO) in isooctane, and the third phase consisting of a basic stripping solution that allows reextraction of HIBA from the organic phase. A comparison of HIBA mass transfer experiments was carried out in the membrane reactor with two and three phases for different pH and TOPO concentrations. The use of the three-phase arrangement allows the extraction of high quantities of HIBA from the aqueous medium (higher than 85%) independently of the pH, whereas in the two-phase system the percentage of HIBA extracted from the aqueous medium was lower, 42% in the best case, and strongly influenced by the pH. The percentage of the extractive agent TOPO in the organic phase influenced on the mass transfer rate in both bi- and triphasic arrangements. By simply integrating the re-extraction phase in the system it was possible to increase the extraction yield by 2-fold, reduce the amount of TOPO by 4-fold, and operate at the more favorable pH 4. A bioconversion experiment was done in these conditions (pH = 4, TOPO = 5%) to confirm the advantages of including the third stripping solution. Fed-batch operation of the triphasic membrane reactor was maintained for more than 20 h, reaching an HIBA concentration in the stripping solution of 29 g L(-)(1).

Abstract: The bioconversion of penicillin G to deacetoxycephalosporin G (DAOG) using resting cells of Streptomycesclavuligerus could be a very valuable step in the economical production of semisynthetic cephalosporin antibiotics. The extent of the reaction, however, is very low due to inactivation of the ring expansion enzyme deacetoxycephalosporin C synthetase ("expandase") by reaction components. We show that elimination of agitation during the reaction lowers the rate but increases the amount of DAOG produced, presumably because the inactivation requires high levels of oxygen. Many additives to the medium were examined for their effect on the reaction. Clearly, the most effective compound was the organic solvent, decane.

Abstract: Disclosed are methods for bioconversion of cellulose in spent sausage casings to a useful end-product. The methods involve treating the cellulose with a cellulase to yield glucose, which in turn is converted to lactic acid, ethanol, enzymes or feed grade protein by a microorganism.

Abstract: The pharmacological properties of the extract of Ruscus aculeatus L. have been well established for many years now. The compounds which possess these properties are the steroid glycosides ruscin and ruscoside and their hydrolysis products desglucoruscin, desglucodesrhamnoruscin and desglucoruscoside. As the pharmacological action increases with the decrease of the amount of the sugar molecules, the plant extracts must be submitted to chemical or enzyme hydrolysis in order to obtain the most active compounds. In our laboratory, a bioconversion process to produce the monoglycoside desglucodesrhamnoruscin from dry extracts of the rhizome of R. aculeatus has been developed using enzyme preparations containing a β-glucopyranosidase and an α-rhamnopyranosidase. Identifying the concentrations of substrate, enzyme and ethanol that are most advantageous for the bioconversion has optimized the process. The developed process gave a final product containing 19% of desglucodesrhamnoruscin.

Abstract: Different used paper materials and mixtures thereof were saccharified with Penicillium funiculosum cellulase. Non-similar biodegradation patterns were concluded to be operating as well as declining bioconversion efficiencies with increasing biodegradation. Biowaste mixtures were less effectively biodegraded indicating the importance of separating biowaste into distinctive materials prior to developing it as a resource of bioproduct synthesis.

Abstract: In our microbial screening program, we have isolated a fungal strain which produced mycophenolic acid (MPA). This compound is a selective inhibitor of guanine synthesis and, therefore, it has antibacterial, antiviral, antitumor and selective immunosuppressive activities, too. This last effect was utilised by Roche-Syntex to develop a derivative of MPA to the immunosuppressive drug CellCept®. In order to obtain novel derivatives of MPA with an enhanced activity, we applied bioconversion of MPA with various microorganisms. TLC with densitometric evaluation and HPLC methods were developed for measurement of MPA derivatives. In the course of the bioconversion of MPA by using various types of microorganisms amidation of the carboxyl group, hydroxylation of the C4-methyl group and formation of glycoside derivatives from the hydroxyl group located on C7 were observed as the most frequently occurring transformations. The structures of bioconversion products were determined by UV, IR, 1H NMR, 13C NMR and mass spectroscopic methods. The taxonomic features of cultures of the species applied in the bioconversion were also determined.

Abstract: [en] This work presents an original method for testing the biological reactivity of cellulose. This test specifically targets one of the limiting steps of cellulose bioconversion into biogas, i.e. the cellulose hydrolysis. From this point of view, enzymes-mediated hydrolysis has been performed to evaluate cellulose bioavailability in refuse samples from different layers of an old landfill. The relationship between the cellulose enzymatic accessibility and the lignin contents has also been studied. Similarly, the correlation between cellulose, lignin and humic acid contents has been investigated. On the other hand, moisture content in landfills is considered as one of the most important factors that favours methanogenesis. In this respect, the influence of moisture content on cellulose enzymatic hydrolysis has also been evaluated.

Abstract: The bioconversion of penicillin G, an inexpensive substrate, to the valuable intermediate for semisynthetic cephalosporin production, deacetoxycephalosporin G (DAOG), had been recently shown to be increased by eliminating agitation and adding decane. The present work examining other solvents shows that all alkanes tested are equivalent to decane in activity but that other solvents are either inhibitory or less active than alkanes. Optimum conditions of pH and temperature for the alkane system are not very different from the previously used aqueous system.

Abstract: Several natural associations composed of thermophilic anaerobic bacteria capable of utilizing various cellulose materials at 60 ± 2°C and pH 60–70 were isolated from the sludge of Kamchatka geothermal springs The rate of ethanol production (up to 17 g/l per day) and the concentration of ethanol in the medium (up to 12%), as well as the fermentation period (10–15 days), were determined under anaerobic conditions in the presence of cellulose, coniferous sawdust, newsprint, or paper pulp as a carbon source Microorganisms were found that inhibited the production of ethanol The initial pH value was found to influence both the ethanol production rate and ethanol/acetate ratio A pH decrease from 70 to 50 led to a 67-fold increase in ethanol production and caused a 238-fold increase in the ethanol/acetate ratio

Abstract: agriculture. SUBSTANCE: invention relates to biological treatment of plant production processing, bioconversion of agriculture waste and products of vital activity of animals and to human survival also. Method involves plant raw grinding, its mixing with products of animal vital activity, additional addition of plant raw subjected for the preliminary microbiological treatment, fermentation of mixture, addition of invertebrate larvae, their culturing and the following separation. After fermentation the treated mixture is separated for large and small fractions. The large fraction is ground and the small one is separated for two parts one of that is mixed with the ground large fraction. Then products of animal vital activity are added additionally and fed for larvae culturing and another fraction is used as the food addition. Separated larvae are used as biologically active addition for humans and animals and remained substrate is used for biofertilizer preparing and fungi culturing. Method ensures to utilize organic waste and obtain low-priced fodder and fertilizer. EFFECT: improved method of processing, decreased cost of products. 6 cl, 1 ex

Abstract: SummaryGrowth and yield of Pleurotus florida on rice straw were studied as a function of temperature. At an ambient temperature of 20˚C, a maximum bioconversion efficiency (yield to substrate ratio, both on a dry-weight basis) of 14.5% was recorded. The net yield was observed over 2–3 flushes, with an interflush period of ca. 7.d. Increase in bioconversion efficiency (BCE) decreased left-over spent substrate and increased the loss of growth substrate as CO2 and H2O. An increased solubility of the growth substrate was observed with increase in BCE. In general, increase in sugars, amino acids, and decrease in phenols, cellulose, hemicellulose and lignin were observed; however amino acids decreased at high levels of BCE. Likewise, the decrease in lignin content was not important above a 10% increase in BCE. Flush co-ordinated operation of the degradatory enzymes in the rice straw substrate was studied. Whilst CMC-ase, b-glucosidase, hemicellulase and protease showed a continuous increase over all the flushes...

Abstract: Enantiomerically pure epoxides are produced by bioconversion of the corresponding styrenes using a recombinant Escherichia coli strain containing the styrene monooxygenase gene cloned from Pseudomonas fluorescens ST. Different procedures were used to optimise yields and to permit product isolation. Conversion rates depend on the position and nature of the styrene substituent.