https://faculty.washington.edu/renatab/courses/PSE490/downloads/pretreatment.pdf

Features of promising technologies for pretreatment of lignocellulosic biomass.

Improvement of enzyme activity, stability and selectivity via immobilization techniques

Phosphate solubilizing bacteria and their role in plant growth promotion

Laccases of fungi attract considerable attention due to their possible involvement in the transformation of a wide variety of phenolic compounds including the polymeric lignin and humic substances. So far, more than a 100 enzymes have been purified from fungal cultures and characterized in terms of their biochemical and catalytic properties. Most ligninolytic fungal species produce constitutively at least one laccase isoenzyme and laccases are also dominant among ligninolytic enzymes in the soil environment. The fact that they only require molecular oxygen for catalysis makes them suitable for biotechnological applications for the transformation or immobilization of xenobiotic compounds.

Fungal laccases - occurrence and properties.

Industrial applications of microbial lipases

Organic acids excreted by filamentous fungi may be used to win metals from industrial secondary raw materials. For a future commercial use a high production rate of organic acids is necessary. The conditions under which the commercially used fungus Aspergillus niger excretes high amounts of citric acid can not be maintained in metal leaching processes. However, Penicillium simplicissimum showed an enhanced citric acid efflux in the presence of an industrial filter dust containing 50% zinc oxide. Because Good buffers of high molarity were able to mimic the effect of zinc oxide, the high buffering capacity of zinc oxide and not an effect of the zinc ions was held responsible for the enhanced citric acid efflux. The presence of ammonium and trace elements reduced this buffer-stimulated citric acid efflux, whereas the plant hormone auxine canceled this reduction. This citric acid efflux was influenced by a depolarization of the membrane: the freely permeable compound tetraphenylphosphoniumbromide decreased the citric acid efflux, without decreasing intracellular citric acid or consumption of glucose and oxygen. Vanadate, an inhibitor of the plasma membrane H+-ATPase also reduced the buffer-stimulated citric acid efflux. The role of the efflux of citrate anions as an alternative charge balancing ion flow in case of impaired backflow of extruded protons because of a high extracellular buffering capacity is discussed.

Buffer-stimulated citrate efflux in Penicillium simplicissimum: an alternative charge balancing ion flow in case of reduced proton backflow?

Compost turning — A central factor for a rapid and high-quality degradation in household composting

Proteins are important constituents of both seed and root exudates, they are a primary structural and functional component of plant cell walls, and represent a third of the total nitrogen in soil (O’Sullivian et al. 1991). Proteins are supplied to soil from all dead organisms, plants and animals. Proteins in soil are decomposed readily by many bacteria and fungi. During degradation, extracellular proteases produce oligopeptides from proteins, resulting in the subsequent release of low molecular weight compounds which are assimilated by microorganisms. Upon the release of proteases from microbial cells these soil enzymes become physically adsorbed onto soil colloids or covalently bound to soil organic matter. These immobilized enzymes show a high degree of resistance to proteolysis. In contrast, proteases are inhibited by desiccation.

Enzymes Involved in Nitrogen Metabolism

An agar plate screening method was developed for the rapid isolation of heavy metal-accumulating microorganisms and preliminary estimation of their biosorption capacity. The test is based on the visulaization and interpretation of the metal distribution between agar and colonies by chemical preciptitation with hydrogen sulphide or ammonium sulphide. The heavy metals silver, thallium, lead, copper, nickel and cadmium have been tested successfully. The efficiency of the method is demonstrated for isolating silver-accumulating bacterian and estimating silver biosorption capacity.

Franz Schinner

Papers

Buffer-stimulated citrate efflux in Penicillium simplicissimum: an alternative charge balancing ion flow in case of reduced proton backflow?

Compost turning — A central factor for a rapid and high-quality degradation in household composting

Enzymes Involved in Nitrogen Metabolism

A rapid screening method for the isolation of metal-accumulating microorganisms

Purification and characterization of an alkaline serine protease produced by a psychrotrophic Bacillus sp.