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The content of protein, moisture content and essential amino acids in conventional and genetically modified soybean grain and selected soybean products (soybean pâté, soybean drink, soybean dessert, tofu) was analyzed in this paper. The following comparative analysis of these products has not yet been carried out. No differences were observed in the amino acid profiles of soybeans and soybean products. The presence of essential amino acids was confirmed except for tryptophan. Its absence, however, may be due not to its absence in the raw material, but to its decomposition as a result of the acid hydrolysis of the sample occurring during its preparation for amino acid determination. Regardless of the type of soybean grain, the content of protein, moisture content and essential amino acids was similar (statistically insignificant difference). Thus, the type of raw material did not determine these parameters. There was a significant imbalance in the quantitative composition of essential amino acids in individual soybean products. Only statistically significant variation was found in genetically modified and conventional soybean pâté. Moreover, in each soy product their amount was lower irrespective of the raw material from which they were manufactured. Therefore, the authors indicate the necessity of enriching soybean products with complete protein to increase their nutritional value.

Rapamycin is a clinically important macrocyclic polyketide with immunosuppressive activity produced by Streptomyces hygroscopicus . To rationally guide the improvement of rapamycin production, comparative metabolic profiling analysis was performed in this work to investigate the intracellular metabolic changes in S. hygroscopicus U1-6E7 fermentation in medium M1 and derived medium M2. A correlation between the metabolic profiles and rapamycin accumulation was revealed by partial least-squares to latent structures analysis, and 16 key metabolites that most contributed to the metabolism differences and rapamycin production were identified. Most of these metabolites were involved in tricarboxylic acid cycle, fatty acids, and shikimic acid and amino acids metabolism. Based on the analysis of key metabolites changes in the above pathways, corresponding exogenous addition strategies were proposed as follows: 1.0 g/L methyl oleate was added at 0 h; 1.0 g/L lysine was added at 12 h; 0.5 g/L shikimic acid was added at 24 h; 0.5 g/L sodium succinate, 0.1 g/L phenylalanine, 0.1 g/L tryptophan, and 0.1 g/L tyrosine were added at 36 h, successively, and a redesigned fermentation medium (M3) was obtained finally on the basis of M2. The production of rapamycin in M3 was increased by 56.6 % compared with it in M2, reaching 307 mg/L at the end of fermentation (120 h). These results demonstrated that metabolic profiling analysis was a successful method applied in the rational guidance of the production improvement of rapamycin, as well as other industrially or clinically important compounds.