Utilization of Crab Waste for Cost-Effective Bioproduction of Prodigiosin

• Main Authors: Van Bon Nguyen, Dai Nam Nguyen, Anh Dzung Nguyen, Van Anh Ngo, That Quang Ton, Chien Thang Doan, Thi Phuong Pham, Thi Phuong Hanh Tran, San-Lang Wang
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Marine Drugs
• Subjects: <i>Serratia marcescens</i>; prodigiosin; bioreactor system; crab shells; bioprocessing; antioxidants
• Online Access: https://www.mdpi.com/1660-3397/18/11/523

This study aimed to establish the culture process for the cost-effective production of prodigiosin (PG) from demineralized crab shell powder (de-CSP), a fishery processing byproduct created via fermentation. Among the tested PG-producing strains, <i>Serratia marcescens</i> TNU02 was demonstrated to be the most active strain. Various ratios of protein/de-CSP were used as the sources of C/N for PG biosynthesis. The PG yield was significantly enhanced when the casein/de-CSP ratio was controlled in the range of 3/7 to 4/6. TNU02 produced PG with a high yield (5100 mg/L) in a 15 L bioreactor system containing 4.5 L of a newly-designed liquid medium containing 1.6% C/N source (protein/de-CSP ratio of 3/7), 0.02% (NH₄)₂SO₄, 0.1% K₂HPO₄, and an initial pH of 6.15, at 27 °C for 8 h in dark conditions. The red pigment was purified from the culture broth and then quantified as being PG by specific Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) and UV spectra analysis. The purified PG demonstrated moderate antioxidant and effective inhibition against four cancerous cell lines. Notably, this study was the first to report on using crab wastes for PG bioproduction with high-level productivity (5100 mg/L) in a large scale (4.5 L per pilot) in a short period of fermentation time (8 h). The salt compositions, including (NH₄)₂SO₄ and K₂HPO₄, were also a novel finding for the enhancement of PG yield by <i>S. marcescens</i> in this report.