Optimization of culture condition for useful microbial strains to treat organic solid waste into fertilizers

Abstract

This study selected and optimized the fermentation medium for biomass collection of three useful microbial strains: Bacillus velezensis N₂₄, Bacillus amyloliquefaciens NT and Trichoderma sp. N₁ with the characteristics of strains capable of metabolizing diverse organic compounds (starch, cellulose, protein, and pectin), as well as capable of biosynthesizing IAA, degrading insoluble phosphate, and fixing nitrogen, resistance to pathogenic microorganisms. The recommended process parameters for N₂₄ strain biomass collection of strains are medium supplemented with 4.5 g/l starch, 8.25 g/l peptone, innitial pH 7, temperature 34^oC, 150 rpm shaking speed. Under these conditions, the wet biomass content of strain N₂₄ can be reached 27.55 g/l. For the NT strain, fermented medium supplemented with 3.87 g/l starch, 8g/l peptone, innitial pH 7, temperature 35^oC, shaking speed 150 rpm, the wet biomass content reached 29.32 g/l. For the N₁ strain, fermented medium containing 5 g/l starch; 6.85 g/l peptone; innitial pH 6; temperature 32^oC, shaking speed 77 rpm, the wet biomass content reached 39.21 g/l. Initially, a microbial product was created on the carrier to process organic waste into standard fertilizer.