Formation of extra- and intracellular amino acids by micromycetes

Abstract

A comparative study has been made of extra-and intraceUular amino acids in the dynamics of the growth and development of the cellulolytically active fungus Trichoderma harzianum and of a protoplast culture and a hybrid culture of the fungus obtained by the methods of cell engineering.Among biochemical processes in a natural medium the synthesis of amino acids by micromycetes is of great importance. A capacity of various microorganisms for synthesizing and accumulating amino acids intracellularly and also of producing them during their growth and development in a nutrient medium has been found [1][2][3]. In view of this, it appeared of interest to investigate the compositions of the extra-and intracellular amino acids in the cellulolytically active fungus Trichoderma harzianum and also in a protopl~st culture and a hybrid culture of the fungus obtained by the methods of cell engineering.We 'have carried out a comparative study of the dynamics of the accumulation of amino acids in the culture liquid and the mycelium of the above-mentioned culture. The results of the investigation are presented in Tables 1-6. It was established that Trichoderma harzianum produced the following amino acids: lysine, arginine, aspartic acid, serine, leucine, alanine, and methionine. The maximum amount of amino acids was observed on the eighth day of growth and amounted in total to 117.0 #g/ml. The protoplast culture of Trichoderma harzianum secreted into the culture liquid lysine, arginine, aspartic acid, serine, glycine, alanine, methionine, leucine, and tyrosine, and the hybrid culture secreted lysine, arginine, aspartic acid, serine, glycine, alanine, methionine, leucine, and tyrosine.With respect to their qualitative composition, the amino acids of the culture liquid taken for investigating the culture had similarities and differences. The common properties must be taken to include the fact that the micromycetes studied produced seven identical amino acids: lysine, arginine, aspartic acid, serine, leucine, alanine, and methionine. The maximum amounts of these amino acids were observed, in the main, on the sixth-eighth day of growth of the micromycetes, although for each strain the percentage of the combined sum of amino acids changed with the age of the culture. For example, on the sixth day of growth the hybrid Trichoderma harzianum culture formed the maximum combined sum of amino acids --267.3 /~g/liter, while the greatest formation of glycine and tyrosine, at 27.4 and 11.4/~g/liter, respectively, was observed on the fourth day.In the case of the hybrid culture of Trichoderma harzianum, the pattern of accumulation of lysine and methionine was as follows. The culture began to produce these amino acids on the second day of growth, the amounts of methionine and lysine in the culture liquid then amounting to 2.3 and 3.7%, respectively, of the combined sum of the amino acids. As follows from Tables 1-3, their maximum accumulation in the culture liquid took place on the sixth to eighth days of growth. The percentages of these amino aci...