Enhancement of Prodigiosin production from soybean residue by-product via fermentation technology

Prodigiosin (PG) is a red pigment compound originating from Serratia marcescens. Recently, this compound has been extensively studied for its production process and investigation of its potential bioactivities. However, most previous studies used commercial nutrient broth as a carbon/nitrogen (C/N) source for cultivation in small-scale flasks. Regarding the cost-effective and green production, we reused soybean residue by-product (SRBP) for the biosynthesis of PG on a large scale using a 14-L bioreactor system and reported its potent anti-nematode activity. The experimental results revealed that Serratia marcescens TNU2 produced PG at the highest yield (5700 mg/L) under fermentation conditions: 6 L of liquid medium containing 1.75% C/N (SRBP/casein at the ratio of 8/2), 0.05% MgSO4, 0.1% K2HPO4, with an initial pH of 7.0, and the fermentation was performed at 27.5°C in 10 h. On the activity tests, the purified PG at the tested concentration of 1 mg/mL demonstrated a potential nematicidal effect against root-knot nematode on both J2 nematodes (100%) and eggs hatching (87.43%) at 1 and 3 days after treatment with PG, respectively. This study suggested that SRBP is a good C/N source for the bioproduction of PG with potential use for managing root-knot nematodes