DefinePK

Abstract

Background:  Sclerotium bataticola , a soil-born fungus, is responsible for charcoal rot in a variety of plants. It is also responsible for causing substantial damage to a wide range of horticultural crops around the world. Methods:  Fifteen different  Bacillus  isolates were isolated and evaluated for their ability to inhibit  S. batatacola 's growth. The promising bacterial isolate was molecularly identified using NCBI-Blast and phylogenetic tree analysis of the 16S rRNA gene. Batch fermentation was performed in a stirred tank bioreactor to maximize culture biomass and secondary metabolite synthesis. Gas chromatography-mass spectrometry was used to discover secondary metabolite compounds. Results:  The KSAS6 isolate was the most effective for inhibiting the fungal growth of mycelial cells, with a 48.2% inhibition percentage. The probable biocontrol agent,  B. amyloliquefaciens  strain KSAS6, was identified and recorded in GenBank under the accession number PQ271636. The culture biomass and secondary metabolites were maximized by the batch fermentation technique, reaching the highest achievable level of 2.1 g L -1  at 11 hours. This was accomplished while maintaining a steady specific growth rate (µ) of 0.13 h -1 . Based on the observations, the biomass yield coefficient was found to be 0.37 g cells/g glucose. Among the 21 secondary metabolite compounds identified in GC-MS analysis, diisooctyl phthalate was the highest compound (43.31%). Conclusion:  The strain of rhizobacterium  B .  amyloliquefaciens  known as KSAS6 can inhibit the growth of  S .  bataticola , which makes it a promising candidate for the biocontrol of fungal infections in plants. Keywords:  Sclerotium bataticola ; Bacillus amyloliquefaciens;  Batch fermentation; Secondary metabolites; antifungal