Solid-state fermentation with Serratia marcescens Xd-1 enhanced production of prodigiosin by using bagasse as an inertia matrix

Prodigiosin has attracted great interest for several decades for its proapoptotic anticancer and other activities. However, the low productivity of prodigiosin under submerged fermentation (SmF) limits its commercial application. In this study, S. marcescens Xd-1 was newly isolated from a mouldy tofu sample and was used to produce prodigiosin by solid-state fermentation (SSF) using bagasse as an inertia matrix. The result showed that S. marcescens Xd-1 was adapted to SSF for prodigiosin production and could bear a higher concentration of glycerol. Process parameters were systematically examined to improve the conversion of glycerol to prodigiosin by a response surface methodology. The maximal yield of prodigiosin (40.86 g kg−1 dry solid) was achieved with glycerol 1.17 g g−1 bagasse, soy peptone 0.33 g g−1 bagasse, an initial moisture content of 83.5 %, and 1-mm particles of bagasse by using a response surface methodology (RSM). In addition, the extraction ratio of prodigiosin increased rapidly to 90 % in 30 min by using ultrasonic-assisted reflux extraction. Our results expand the culture method of S. marcescens for prodigiosin production and enhanced the conversion of glycerol to prodigiosin.