Probiotic bacteria promote the growth of associating host(red seaweed, Gracilaria edulis) also synthesize antibacterial protein

In this study, isolates of Gram positive Lysinibacillus xylanilyticus associated with red seaweed species were evaluated for antibacterial activity against plant pathogenic bacterium X. oryzae pv. oryzae which cause bacterial blight in rice using disc and well diffusion assays. The isolate HVT234 among the isolates of L. xylanilyticus associated with red seaweed species exhibit high antibacterial activity. The optimum level of extracellular antibacterial protein synthesize in HVT234 was recorded when cultured in 1.5% inoculum in seawater medium with lactose carbon and ammonium chloride nitrogen at pH 7.0 at 35 °C for 48 h. The antibacterial substance extracted in ethyl acetate from the culture supernatant of L. xylanilyticus HVT234 was isolated and separated as 66 kDs protein. The L. xylanilyticus synthesizing antibacterial substance elicited by some non-active co-associating bacteria promote the host Gracilaria edulis growth is considered as probiotic because another associated Bacillus cereus produce antibacterial protein did not support the host growth. This chemical elicitor protein most probably a quorum signal N-acyl homoserine lactone of probiotic L. xylanilyticus which support the host G. edulis growth reported for the first time from this study has immense value in the seaweed mariculture because this species is one of the major biomass feedstocks for agar production.Graphical abstract
Source: Biocatalysis and Agricultural Biotechnology - Category: Biotechnology Source Type: research