Microbial producers

Ziffer H, K Kabuta, DT Gibson, VM Kobal, DM Jerina (1977) The absolute stereochemistry of several cis dihydrodiols microbially produced from substituted benzenes. Tetrahedron 33 2491-2496. 

Reineke W, W Otting, H-J Knackmuss (1978) cw-Dihydrodiols microbially produced from halo- and methylbenzoic acids. Tetrahedron 34 1707-1714. 

Polyesters, such as microbially produced poly[(P)-3-hydroxybutyric acid] [poly(3HB)], other poly[(P)-hydroxyalkanoic acids] [poly(HA)] and related biosynthetic or chemosynthetic polyesters are a class of polymers that have potential applications as thermoplastic elastomers. In contrast to poly(ethylene) and similar polymers with saturated, non-functionalized carbon backbones, poly(HA) can be biodegraded to water, methane, and/or carbon dioxide. This review provides an overview of the microbiology, biochemistry and molecular biology of poly(HA) biodegradation. In particular, the properties of extracellular and intracellular poly(HA) hydrolyzing enzymes [poly(HA) depolymerases] are described. 

Allelopathy arises because growth stimulating, or inhibiting plant and microbial produced biochemicals which are released into the environment. The stress conditions such as moisture, temperature, fertilizer, soil, pests,... 

ENZYMES IN BIOMASS CONVERSION Table II. Microbial producers of a-glucuronidases... 

Microbially produced secondary metabolites are extremely important to our health and nutrition. As a group, they have tremendous economic importance. In the year 2007, the market for all anti-infective agents was 66 billion, and most of this was represented by 160 antibiotics and their derivatives. In 1929, Alexander Fleming published his historic observation that a contaminating mold, identified as PenicilUum notatum, killed his... 

In soils, electrons are produced by the metabolic activity of soil biota. These electrons are usually accepted by O2 dissolved in the soil solution which is then replaced by O2 from the soil air. Oxygen may, however, become deficient if all pores are filled with water as in waterlogged or compacted soils. Fe in Fe oxides may then function as an alternative electron acceptor and Fe ions will be formed according to eq. (16.3). The electrons are transferred from the decomposing biomass to the Fe oxide by microbially produced enzymes. Other potential electron acceptors in soils are nitrate, Mn and sulphate. 

There are several other examples of enzyme peptide synthesis. The conversion of porcine insulin into a human insulin precursor, by replacing the B chain C-terminal with threonine, is still an important alternative to microbially produced human insulin. Peptides that are produced from ethyl esters of L-amino acids by BioEurope are used as ingredients of cosmetics. 

Table 23.3 Some microbially produced flavour compounds and corresponding bioprocess features... 

Fig. 23.4 Organophilic pervaporation (PV) for in situ recovery of volatile flavour compounds from bioreactors. The principle of PV can be viewed as a vacuum distillation across a polymeric barrier (membrane) dividing the liquid feed phase from the gaseous permeate phase. A highly aroma enriched permeate is recovered by freezing the target compounds out of the gas stream. As a typical silicone membrane, an asymmetric poly(octylsiloxane) (POMS) membrane is exemplarily depicted. Here, the selective barrier is a thin POMS layer on a polypropylene (PP)/poly(ether imide) (PEI) support material. Several investigations of PV for the recovery of different microbially produced flavours, e.g. 2-phenylethanol [119], benzaldehyde [264], 6-pentyl-a-pyrone [239], acetone/buta-nol/ethanol [265] and citronellol/geraniol/short-chain esters [266], have been published...

Microbially produced biosurfactants can also have important effects on increasing bioavailability and biodegradation (Zhang Miller, 1992). A new PCB-degrading strain was recently isolated and found to produce a bio-emulsifier (Rothmel et al., 1993). Experiments show that the bio-emulsifier stimulates the extent of PCB degradation well beyond the levels seen before with other Type strains of its class, and that the bio-emulsifier can stimulate the extent of PCB biodegradation of added co-cultures as well. 

Metal reclamation from acid mine drainage and contaminated surface- and groundwater and wastewaters has been extensively studied. Technologies for metal removal from solution are based on the microbial—metal interactions discussed earlier the binding of metal ions to microbial cell surfaces the intracellular uptake of metals the volatilization of metals and the precipitation of metals via complexation with microbially produced ligands. 

In conclusion, the vast literature and its derivatives, particularly artesunate, artemether, and arteether, point out to the need to make these derivatives in quantities that would reduce their current production cost to make these drugs accessible to the economically underprivileged societies that are often the victims of malaria. A recent promising method in which artemisinic acid, a precursor to artemisinin, has been produced in engineered yeast. Therefore, microbially produced artemisinic acid holds promise to the syntheses of antimalarial drugs at affordable prices <2006N940>. Furthermore, anticancer activities of artemisinin 1 and its derivatives have been reviewed <2005MI995>. 

Microbially produced (2.S .3.S )-// .v-dihvdroxy-2.3-dihvdrobenzoic acid was used in the synthesis of enf-streptol, enf-senepoxide, and /so-crotepoxide (Fig. 33). The short and efficient synthesis of these biologically active compounds included the esterification of the carboxylic acid and protection of the diol moiety, delivering control of the regio- and stereoselectivity of the following epoxidation or dihydrox-ylation steps [178, 180]. 

The nature of the solid phase S species initially formed by reaction with microbially produced H2S determines subsequent transformations and the extent of recycling, since different solid S species vary in susceptibility to... 

Microbially Produced Functionalized Cyclohexadiene-trans-diols as a New Class of Chiral Building Blocks in Organic Synthesis On the Way to Green and Combinatorial Chemistry... 

I 6.4 Microbially Produced Functionalized Cyclohexadiene-trans-diols... 

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