[Effect of particle size on the enzymatic hydrolysis of polysaccharides from ultrafine lignocellulose particles].

The efficiency of the enzymatic hydrolysis of wood polysaccharides ground into ultrafine particles (UFPs) has been investigated. The content of reducing sugars (RS's) in powdered raw materials and the yield of sugars during enzymatic hydrolysis have been shown to depend on the particle size. Laser interference microscopy and dynamic light scattering studies have shown that increasing the grinding time from 20 to 40 min resulted in the formation of particles ranging from 2 to 200 nm in size. Enzymatic hydrolyzates of UFPs mostly contained glucose and galactose. The grinding intensity (mill rotation rate) and time had a significant effect on the extent of the enzymatic hydrolysis of wood.

[New possibilities of studying microbial objects by laser interference microscopy].

A novel method, laser interference microscopy, has been developed for studying the morphofunctional state of bacterial cells and the structure of bacterial communities. The following potentialities of the method are shown: rapid determination of the cell structure and subcellular structures (nucleus zone, vacuoles, lamellar structures) and the physiological state of the cell, as well as the study of the structure of bacterial communities (biofilm). The method does not require any additional preparation of cells before the investigation (fixation, staining, treatment with contrasting substances), which reduces the possible appearance of artifacts to a minimum and enables one to use laser interference microscopy for in vivo investigations.

[The effect of copper ions on the production of laccase by the fungus Lentinus (Panus) tigrinus].

The basidiomycete Lentinus tigrinus was cultured in media containing copper ions added at different growth stages. Copper ions at increased concentrations decelerated of the fungal biomass accumulation. The later Cu2+ ions were added, the better the fungal mycelium developed, and the toxic effect of Cu2+ was less pronounced. The maximum laccase activity (47 U/ml) was observed in the presence of 1.5-2.0 mM Cu2+ added on day 4 of cultivation.

[Modification of wood lignin by the fungus Panus tigrinus]. / Modifikatsiia lignina drevesiny gribom Panus tigrinus.

The treatment of sawdust with the fungus Panus tigrinus VKM F-3616 D changed the contents of functional groups in lignin from wood raw material. These changes are accompanied by the release of carboxyl and phenyl hydroxyl groups involved in chemical bond formation between wood particles in pressed materials manufactured from wood wastes.

[Use of Panus tigrinus fungi for production of pressed materials from cotton plant waste]. / Ispol'zovanie griba Panus tigrinus dlia proizvodstva pressovannykh materialov iz otkhodov khlopchatnika.

Changes in the chemical composition of cotton plant stems used as a substrate for solid-phase cultivation of the fungus Panus tigrinus were studied as well as the effect of these changes on properties of the pressed materials made of these stems. During the first 3 days of growth, the fungus better consumed cellulose; then, the rate of cellulose consumption was comparable with that of lignin. Intensity and pattern of these changes depended on the age of inoculum. The rate of cotton plant waste biodegradation was higher when a 3-day-old incoculum was used. The pressed materials made of the raw stuff treated with a 3-day-old inoculum of P. tigrinus for 2-3 days displayed better characteristics. Annually, large amounts of lignocellulose stuff is lost while processing of agricultural waste: straw, awn, plant stems, etc. In the countries with developed cotton growing, the annual amount of only guza-paya (dry cotton plant stems) reaches several million tons. To solve this problem, bioconversion of these wastes is studied to manufacture useful products and materials.

[Relation between ligninolytic and phospholipase activities in the fungus Lentinus tigrinus].

Effect of hydrocortisone, NaF, and FeSO4 on ligninolytic and phosphatase activity of the fungus Lentinus (Panus) tigrinus VKM F-3616D was investigated, Hydrocortisone and NaF were shown to inhibit the enzymes of the ligninolytic complex-laccase (EC 1.10.3.2), secretory peroxidase (EC 1.11.1.7), and Mn peroxidase (EC 1.11.1.13). FeSO4 exhibited no significant effect on the activity of these enzymes. Decreased activity of the enzymes of the ligninolytic complex was associatedwith inhibition of the activity and changes in the substrate specificity of phospholipase A2 (EC 3.1.1.4) in the presence of hydrocortisone of NaF. Cultivation of L. tigrinus in the presence of these compounds resulted in higher affinity of this enzyme to saturated fatty acids, while in the control and in the presence of FeSO4 affinity to unsaturated fatty acids was higher.