L-lysin-a-oxidase biosynthesis by soil saprophyte Trichoderma harzianum Rifai

Prevalence of Trichoderma in soil microflora indicates a certain role of this culture in ecology, and the practical importance of L-lysin-α-oxidase as the Trichoderma metabolite doesn't arouse any doubts with regard to the possibility its use by creation of medical drugs. Cultivation conditions and formation of Trichoderma harzianum Rifai metabolite - L- lysine-α- oxidase were studied in submersed and surface cultivation. This study deals with the correlation of Trichoderma harzianum Rifai spore formation and L-lysin- α-oxidase enzyme biosynthesis in the epigenetics of the culture during submerged cultivation in the media with differing concentrations of (NH4)2SO4. The enzyme biosynthesis correlated with the number of the emerged spores. The amount of the used source of nitrogen in the form of (NH4)2SO4 influenced the process of Trichoderma spore formation and enzyme biosynthesis. Under the conditions of submerged cultivation and with the fungus spores used as the innoculum, the culture growth and biosynthesis of L-lysin-α-oxidase were slight. The extreme difficulty in developing the technique for growing the fungi of the Trichoderma genus in order to obtain the enzyme under the conditions of submerged cultivation is explained by the fact that the species of this genus are able to form chlamydospore under the conditions of submerged cultivation and the subsequent reduction of the number of spores takes place. The fungus mycelium with the medium was used as innoculum in order to study the conditions under which maximum L-lysin-α-oxidase formation in merged cultivation occurs. The use of filamentous form of the innoculum led to the increase in the enzyme activity and it was used for fermentation of maximum L-lysin-α-oxidase formation. The study of the effect, that the degree of aeration has on the L-lysin-α-oxidase formation in merged cultivation of the fungus showed, that the aeration growth facilitates the rise in the enzyme activity, and the possibility for the secondary use of the initial substance [wheat bran] reduces the fungus cultivation period. According to literaturary sources [1,2], the optimum medium pH for the mycelial fungus cultivation is within the range of 5-6. We have studied the effect of initial pH on the fungus growth and the enzyme formation. The maximum enzyme formation has been observed on the first day of the fungus growth at pH 5,6. Under these conditions the culture growth was the best and increase of the protein amount. In the acidic medium at pH 4.5 the fungus forms biomass in the form of individual large granular colonies, however, the enzyme activity under these conditions is low. In a medium having initial pH 7,0, the enzyme activity was also quite low. When the medium is autoclaved for one hour at 1 atmosphere, the growth of fungus and enzyme activity was higher than during thirty-minute autoclaving. In addition, the growth of fungus was more active on the second day and the fungus forms more protein than by autoclaving the medium for 30 minutes. Apparently, complex sugars, polysaccharides and other components contained in wheat bran, are partially hydrolyzed and become more accessible to the culture growth and enzyme biosynthesis. The studies of various ways of cultivation and enzyme biosynthesis allowed accumulating the maximum amount of L-lysin-α-oxidase for its subsequent studies.