Abstract: Publisher Summary This chapter describes physicochemical and biological treatments for enzymatic or microbial conversion of LignocelIulosic Biomass. Microbial utilization of the inexhaustible lignocellulosic biomass for the production of industrial chemicals, liquid fuels, protein-rich food and feed, and the preparation of cellulose polymers is an attractive approach to help meet energy and food demands. Lignocelluloses contain cellulose, hemicellulose, and lignin as the major components. Lignocellulosic raw materials by the virtue of their structure are relatively refractory to direct bioconversion. Cellulose in lignocellulosic substrates has the regions of a highly resistant crystalline structure and the lignin surrounding cellulose forms a physical barrier that allows only limited sites available for enzymatic attack. The use of whole P . chrysosporium cells and lignolytic enzymes in the pulp and paper industry appears to hold promise in processes designed for biopulping and biobleaching and in decolorizing bleach plant effluents. This can have a favorable impact on the world economy, sparing scarce energy sources and alleviating the current environmental problems with waste effluents.

Abstract: The anaerobic digestion of Chlorella vulgaris was studied using batch digesters. Standard analysis of chemical oxygen demand (COD), solids, pH, acidity, alkalinity and chlorophyll were done. Biogas composition and production were also determined. The conversion of biomass to biogas ranged from 70–90% in COD. This implies that C. vulgaris could constitute a valuable method of bioconversion of sun energy to biogas.

Abstract: Arteannuin B, which co-occurs with artemisinin, the potent antimalarial principle of the Chinese medicinal herb Artemisia annua (Asteraceae), has been converted to the latter using crude and semi-purified cell-free extracts of the leaf homogenates of the plant. Detection procedures to quantitate this bioconversion, including one that is novel which uses gcms, are detailed.

Abstract: The invention relates to a improved process for the biological transformation of phosphorus and nitrogen containing animal waste excrement into ecologically manageable materials by a process wherein solids in an aqueous slurry of the excrement are precipitated in a solids ecoreactor, the treated slurry is passed to a bioreactor zone where it is soluble phosphorus is precipitated with metallic salts, the slurry is aerobically and anaerobically treated to form an active biomass that actively bioconverts remaining soluble phosphorus and the aqueous slurry containing bioconverted phosphorus is passed to a polishing ecoreactor zone wherein the at least a portion of slurry is bioconverted to a beneficial humus material.

Abstract: Escherichia coli is able to grow on sugars in the presence of a bulk n-alkane phase. When E. coli is equipped with the alk genes from Pseudomonas oleovorans, the resulting recombinant strain converts n-alkanes into the corresponding alkanoic acids. To study the effects of growth rate and exposure to a bulk apolar phase on the physiology and the productivity of E. coli, we have grown this microorganism in two-liquid-phase continuous cultures containing 5% (v/v) n-octane.In contrast to batch cultures of wild-tape E. coli grown in the presence of n-octane, cells remained viable during the entire continuous culture, which lasted 200 h. Bioconversion of n-octane to n-octanoic acid by a recombinant E. coli (alk(+)) in a two-liquid-phase continuous culture was made possible by optimizing both the recombinant host strain and the conditions of culturing the organism. Continuous production in such two-phase systems has been maintained for the least 125 h without any changes in the product concentration in the fermentation medium. The volumetric productivity was determined as a function of growth rate and showed a maximum at a dilution rate D = 0.32 h(-1), reaching a continuous production rate of 0.5 g octanoate/L . h (4 tons/m(3) . year).

Abstract: In the course of using microorganisms to produce value-added products from soybean oil or its fatty acids, a culture contaminant was isolated and tentatively identified as aStaphylococcus species. This microorganism converts oleic acid (cis-9-octadecenoic acid) to 10-ketostearic acid (10-keto-octadecanoic acid) in growing cultures. Bioconversion was studied in two different media at temperatures from 30 to 41°C, with shaking at 150 rpm. Cells were grown in 50 mL of media for 24 h and then incubated with 0.25 g oleic acid for 24 h. Optimum conditions have allowed better than 90% conversion with 85% recovery. Unreacted oleic acid and 10-hydroxystearic acid (10-hydroxyoctadecanoic acid) are the only other compounds present in the ethyl ether extract of the fermentation broth.

Abstract: Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

Abstract: Genetically engineered Saccharomyces cerevisiae strains that express Escherichia coli β-galactosidase gene are able to bioconvert lactose or whey into fructose-1,6-diphosphate (FDP). High FDP yields from whey were obtained with an appropriate ratio between cell concentration and inorganic phosphate. The biomass of transformed cells can be obtained from different carbon sources, according to the expression vector bearing the lacZ gene. We showed that whey can be used as the carbon source for S. cerevisiae growth and as the substrate for bioconversion to fructose diphosphate. © 1993 John Wiley & Sons, Inc.

Abstract: This paper reports the production of 2-phenylacetaldehyde from 2-phenylethanol by acetic bacteria. Several strains of acetic bacteria were investigated and three were found to be effective for this bioconversion. Different conditions (different C source for the microorganisms, pH, substrate concentration, cell immobilization) were tested with yields ranging from 30 to 52.6%.

Abstract: Novel, laboratory-scale, high-solids reactors operated under mesophilic conditions were used to study the anaerobic fermentation of processed municipal solid waste (MSW) to methane. Product gas rate data were determined for organic loading rates ranging from 2.99–18.46 g of volatile solids (VS) per liter (L) per day (d). The data represent the anaerobic fermentation at high-solids levels within the reactor of 21–32%, while feeding a refuse-derived fuel (RDF)/MSW feedstock supplemented with a vitamin/mineral/nutrient solution. The average biogas yield was 0.59 L biogas/g VS added to the reactor system/d. The average methane composition of the biogas produced was 57.2%. The data indicate a linear relationship of increasing total biogas production with increasing organic loading rate to the process. The maximum organic loading rate obtainable with high-solids anaerobic digestion is in the range of 18–20 g VS/L·d to obtain 80% or greater bioconversion for the RDF/MSW feedstock. This loading rate is approximately four to six times greater than that which can be obtained with comparable low-solids anaerobic bioreactor technology.

Abstract: The anaerobic bioconversion of municipal solid wastes (MSW) produces both a valuable fuel product (methane) and a residue useful as a soil amendment. The application of high-solids fermentation technology offers improved economics over the more traditional low-solids fermentation systems. An important benefit of the high-solids process is the reduction in process water, which results in smaller fermentation reactors, and thus lower capital and operating costs. However, the anaerobic bioconversion process appears to be more efficient at high-solids as compared to low-solids levels. To understand the effects of solids levels on the anaerobic bioconversion process more thoroughly, representative high-solids and low-solids anaerobic reactor systems processing identical MSW feedstocks are compared with respect to fermentation performance, total microbial cell number, and important hydrolytic enzyme activities.

Abstract: A search was implemented for a microbial lipase capable of bioconverting a diester (dimethyl 5-(3-(2-(7-chloroquinolin-2-yl)ethyl)phenyl)4,6-dithianon to its S-ester acid, an intermediate in the production of Verlukast (a leukotriene receptor antagonist). Required properties of the sought-after enzyme included a high enantiomeric selectivity (e.e. >98%), the formation of only trace amounts of diacid and a high bioconversion rate. This search yielded 57 lipase-producing microorganisms, 18 of which presented detectable bioconversion activity. Thirteen of these microbes were selected for further study based upon their lipase production level and enzyme stability at harvest. Despite their common enzymatic property, namely the hydrolysis of triglycerides, these lipase preparations presented diverse ester acid specific synthesis rates (from <0.01 μg/unit/h to 0.98 μg/unit/h) and diacid formation levels (from 0% to 35%). One of these microbes, identified asPseudomonas aeruginosa (strain MB 5001), was found to produce a lipase having all of the above-listed required properties. The initial fermentation process developed in shake flasks was rapidly and successfully scaled up in 23-liter labora bioreactors, achieving a maximum production of 35 units/ml of lipase after 48 h of cultivation.

Abstract: Relationships between amylolytic activity and 1-step fermentation of starch to ethanol by strains of Endomycopsis fibuligera were investigated. A suitable strain was selected and conditions for the bioconversion of cassava starch to ethanol were optimized. From 230 yeast strains, strain NRRL 76 of E. fibuligera produced consistently higher levels of alpha-amylase and glucoamylase as well as ethanol from sugar and starch substrates. Strain NRRL 76 grew optimally at pH 6.0 and 30

Abstract: A covalent binding to cellulose granules of two yeast strains Candida tropicalis and Trichosporon cutaneum was achieved. The maximum activity for destroying furfural by the immobilized cells was obtained when the procedure conditions were: reaction medium at pH 5.0, 20°C and cell suspension concentration of 80 mg/ml. The continuous furfural transformation was studied using a growth medium in a fermenter with immobilized Trichosporon cutaneum in which a 84% bioconversion was achieved. The reduced values of furfural remained constant even after 10-fold transformation.

Abstract: The bioconversion of Lignocelluloslc biomass to organic acids and eventually to methane gas, is hindered by their relative resistance to enzymatic hydrolysis. This paper was conducted to evaluate the effect of milling and alkali lime cooking pretreatments on the rate and extent of methane generation from sugar Cane bagasse. The effect of pretreatment process variables (Particle size 8–0.003 mm, tempetature between 100 and 250° C and alkaline dosage between 0 and 8 g CaO/kg VS) on the biogas generation from Sugar Cane bagasse has been investigated. Methane generation from tho pretreated cane bagasse was studied using serum bottle technique and an upflow anaerobic filter bloreactor. The optimum condition involves alkali‐cooking of cane bagasse (0.5 mm) with 4% CaO at 200° C, dissolving most of the cellulose and converting it in a mixture of organic acids, including formic, acetic, lactic, and succinic acids. About 80% of the COD content of the cellulose was retained in the cooked liquor. A very rap...

Abstract: Combination of bioconversion and sorption in a single step.may improve the efficiency of biotechnological processes. Sorptive separation can be controlled either by equilibrium for selective removal of products (adsorptive bioreaction) or by kinetics for the spatial separation of the reacting species (chromatographic bioreaction). The choice between these options depends on the specific motive for integration and on the physico-chemical characteristics of the bioconversion system. Constraints with respect to process configuration and mode of operation are described in this paper for both classes of integrated bioreactor systems. Adsorptive bioreaction is especially interesting for secondary metabolite producing fermentation processes which are hampered either by metabolic control mechanisms or product degradation. Chromatographic bioreaction is mainly the domain of enzyme catalyzed conversions. The main motives are the possibility to achieve conversions well above the thermodynamic equilibrium and simultaneous purification of the products.

Abstract: This process comprises: a) the culture of microorganisms capable of moderately degrading the lactone molecules, which are chosen from the genera Sporidiobolus or Fusarium, in a culture medium containing at least one precursor of R-gamma-decalactone chosen from the group comprising ricinoleic acid and lesquerolic acid, their salts and their esters with C1 to C3 alcohols, b) the extraction, during culture, of the R-gamma-decalactone produced by the said microorganisms, with an organic solvent separated from the culture medium by a semipermeable membrane, the extraction solvent being substantially immiscible with water.

Abstract: A yeast strain for the co-expression of a plant cytochrome P450 mono-oxygenase activity and an endogenous or heterologous NADPH-cytochrome P450-reductase, wherein one of the NADPH-cytochrome P450-reductase or cytochrome P450 genes is integrated into the chromosome of said strain, and the strain is transformed by a vector having an expression cassette for the other gene. The use of said yeast strain, as well as a cDNA sequence coding for cytochrome P450 CA4H of the Jerusalem artichoke Helianthus tuberosus or Arabidopsis thaliana, for bioconversion purposes, is also disclosed.

Abstract: The present invention relates to a method for the preparation of a melanic pigment by enzymatic bioconversion, implementing a melanin precursor substrate and plant cells, characterized in that: (a) poppy (Papaver somniferum) plant cells previously cultivated are separated from their culture medium and subcultured in a culture medium with a concentration from 10 to 100 g/l; (b) the cells are ground at least partially, before or at the end of the latency time, (c) the at least partially ground cells are placed in a bioconversion medium in the presence with a melanin precursor substrate selected amoung indol, indolin, dihydroxyphenylalanin, tyramin and tyrosin; (d) the precipitated melanic pigment is collected. The invention also relates to the utilization of such resulting pigments for the preparation of cosmetic compositions.

Abstract: Tuna sludge and municipal solid waste (MSW) generated on Tutuila Island, American Samoa, represent an ongoing disposal problem as well as an emerging opportunity for use in renewable fuel production. This research project focuses on the biological conversion of the organic fraction of these wastes to useful products including methane and fertilizer-grade residue through anaerobic high solids digestion. In this preliminary study, the anaerobic bioconversion of tuna sludge with MSW appears promising.

Abstract: A variety of advanced bioreactors are being developed to improve production of fuels, solvents, organic acids and other fermentation products. One key approach is immobilization of the biocatalyst leading to increased rates and yields. In addition, there are processes for simultaneous fermentation and separation to further increase production by the removal of an inhibitory product. For example, ethanol productivity in immobilized-cell fluidized-bed bioreactors (FBRs) can increase more than tenfold with 99% conversion and near stoichiometric yields. Two modified FBR configurations offer further improvements by removing the inhibitory product directly from the continuous fermentation. One involves the addition and removal of solid adsorbent particles to the FBR. This process was demonstrated with the production of lactic acid by immobilized Lactobacillus. The second uses an immiscible organic extractant in the FBR. This increased total butanol yields in the anaerobic acetone-butanol fermentation by Clostridium acetobutylicum.

Abstract: Ion effects on of progesterone and by Rhizopus nigricans were investigated. Metal ions such as reduced the activity, while stimulated the same reaction. Enzyme activity for the of was increased in the presence of , whereas it was decreased in the presence of . Potassium ion of of concentration was found to be effective for the promotion of . On the other hand, cadmium ion of was proved to suppress the reaction. Progesterone is reported to be transformed into which, in turn, is converted further into , 20-dione by R. nigricans. From this point of view, the highest yield of could be obtained when potassium ion of was given initially followed by addition of cadmium ion of to limit conversion of 11{\alpha}-hydroxyprogesterone into , 20-dione.