XYLANASE ACTIVITY OF ASPERGILLUS NIGER AT DIFFERENT ECOLOGICAL CONDITIONS

Maximization of xylanase activity at different media, temperature, pH and salt concentration has been presented in this paper. YpSs, Czapek dox and Malt extract medium were taken for evaluation of optimum growth and activity. Amongst all tested media, YpSs showed the highest growth. Three different natural carbon substitute i.e., wheat husk, rice husk and sugarcane baggase were used for xylanase activity. Maximum enzyme activity was observed in test fungus at rice husk. Production and maximum xylanase activity at rice husk has been observed at different temperatures, pH and Salt concentrations. The highest xylanase activity has been observed on day 5 at temperature 32° C, pH 6.5 and salt concentration of 2%.

Low Temperature Biodisinfection Effectiveness for Phytophthora capsici Control of Protected Sweet Pepper Crops in the Southeast of Spain

Biodisinfection using fresh sheep manure in August is effective in controlling Phytophthora root rot in greenhouses in southeast Spain, but this is not the case after the beginning of September. The effectiveness of biodisinfection of new amendments has been evaluated beginning in October in sweet pepper greenhouses to control Phytophthora capsici. The amendments used were: T1: wheat husk + fresh sheep manure (FSM), 3.5 kg m−2; T2: sunflower pellets 3.5 kg m−2; T3: FSM: 3.5 kg m−2; T4: Control. Temperatures above 40°C were obtained in some amendments; anoxic conditions were found in all amendments, and also a reduction of the viability of P. capsici oospores with respect to the control, as well as a higher yield. The contribution of fresh sheep manure to the amendments did not lead to an improvement in their effectiveness. Autumn biodisinfection under low temperature conditions using fresh organic amendments that enhance soil anaerobic conditions may be a promising strategy for the control of P. capsici in pepper greenhouses in southeastern Spain.

Granular magnesia compositions

The results of studies of granular materials from magnesia compositions are presented. To obtain the compositions, fillers of various origins were used: sawdust, wheat husk, rubber and cork crumbs, ash microsphere. The formulations of molding mixtures that ensure the production of granules by the method of pelletizing are determined. The factors of influence on the strength of granules at various stages of the technological process are revealed. Methods for reducing the density of magnesia granular materials by combining various types of fillers and introducing a gas-forming agent are proposed. The use of caustic magnesite ensures reliable bonding of the filler particles in the granules. Features of hydrate formation of magnesia binders allows the use of low-temperature processing of raw granules. The expediency of increasing the temperature of the salt recluse to accelerate the hardening of the porous granules is shown. Magnesia granules with a bulk density of 400 – 500 kg/m3 were obtained. The work is aimed at creating a resource-saving technology of non-annealed granular aggregates for light concrete