Study on spray-drying of Bacillus velezensis NKMV-3 strain, its formulation and bio efficacy against early blight of tomato

Abstract

Early blight caused by Alternaria solani (A.solani) is a serious disease affecting the tomato crop. Due to resistance built up in pathogens to fungicides, alternate methods of disease control have been explored. This research article details on the efficacy of whole cells of Bacillus velezensis (B.velezensis) NKMV-3 strain and its lipopeptide extract (LPE) against A.solani. B.velezensis NKMV-3 strain and its LPE was spray-dried using laboratory spray dryer. The highest powder recovery (55%) and viability (81.5%) was achieved when spray dried with 10%MgSO4 + 10% Whey protein +0.1% SiO2. The stability of the spray dried whole cell tablets was observed for 180 days (at 4 °C and 37 °C) with a maximum cfu.g−1 of 2.3 × 108 at 4 °C. The spray-dried tablets of LPE of B.velezensis NKMV-3 was stable for 2 years as per CIPAC guidelines with a very low degradation of lipopeptides namely iturin, surfactin and fengycin. Greenhouse studies also revealed that B.velezensis NKMV-3 tablets along with its LPE tablets showed inhibitory effects against A.solani. Hence, B.velezensis NKMV-3 was found to be a suitable candidate to be pursued for the development of a bio control agent against early blight of tomato.