Sensitivity of agronomically valuable strains of Bacillus spp. to lyophilization
The effect of lyophilization with the use of lyoprotective substrates and without lyoprotectors on the survival of endospores of two strains of Bacillus spp., prospective as biological agents for the protection of agricultural plants from a complex of fungal diseases, was studied. Without the use of lyoprotectors, the survival rate of endospores after lyophilization of the strain B. atrophaeus RSA-1 was 61.2%, of the strain B. subtilis RSA-20(2) - 47.6%. Faibich's protective substrate statistically significantly increased the proportion of surviving endospores of the B. atrophaeus RSA-1 strain by 1.46 times, but did not lead to an increase in the proportion of surviving endospores of the strain B. subtilis RSA-20(2). The use of peptone-sucrose-glycerin mixture did not lead to a statistically significant increase in the proportion of survivors of endospore lyophilization in both strains. The injection of ascorbic acid as an antioxidant into the protective substrate of Faibich led to a statistically significant decrease in the proportion of surviving endospores in comparison with the version without lyoprotectors (1.6 times for the strain B. atrophaeus RSA-1 and 25 times for the strain B. subtilis RSA-20(2)).