Utilization of by-product of groundnut oil processing for production of prodigiosin by microbial fermentation and its novel potent anti-nematodes effect

Abstract

This study aimed to reuse groundnut oil processing by-product, groundnut cake (GNC) for the low-cost production of prodigiosin (PG) via microbial technology and to assess its novel potential application for the management of black pepper nematodes. Serratia marcescens TUN02 was found as the most active PG-producing strain. Various small-scale experiments conducted in flasks indicated that GNC at 1% may be used as the sole carbon/nitrogen source for cost-effective PG production by fermentation. Notably, no further commercial ingredients and salts are required to supplement into the culture medium of this fermentation. PG was further investigated for scale-up production in a 14-L bioreactor system and PG was produced at high yield (6886 mg/L) with large-scale volume (4 L) in a short cultivation time (10 h). PG was then purified and its nematicidal activity was evaluated and showed effective inhibition of juveniles and egg hatching of Meloidogyne incognita species, harmful on black pepper, with low IC50 values of 0.2 and 0.32 mg/mL, respectively. The simple medium containing 1% GNC is the first report of cost-effective biosynthesis of PG, as well as potential in vitro anti-egg hatching activity of PG. These results indicated the potential application of GNC for low-cost bioproduction of PG for promising and novel use in the management of black pepper nematodes.