Microbial Reclamation of Chitin and Protein-Containing Marine By-Products for the Production of Prodigiosin and the Evaluation of Its Bioactivities

Abstract

Chitin and protein-containing marine by-products (CPCMBPs), including crab shells, squid pens, and shrimp shells, were investigated as the sole carbon/nitrogen (C/N) source for prodigiosin (PG) production by Serratia marcescens TNU01 in a 250 mL Erlenmeyer flask and a 10 L bioreactor system. Among the used C/N source of CPCMBPs, squid pens powder (SPP) showed the most optimum PG productivity. Different ratios of chitin/protein combination were also used as the C/N sources for PG production. With a similar chitin/protein ratio (4/6) of squid pens, a significant PG productivity was achieved when the chitin/protein ratios were controlled in the range of 3/7–4/6. Maximum PG yield (3450 mg/L) by S. marcescens TNU01 was achieved in the bioreactor system containing 3 L medium of 1.75% SPP, 0.03% K2HPO4, and 0.05% MgSO4 at 25 °C for 12 h in dark. The results of in vitro bioassays reveal that the purified PG possesses acetylcholinesterase inhibitory activity and antioxidant as well as anticancer activities. This study suggests that squid pens may have the potential to be used for cost effective production of bioactive PG at a large-scale.

Utilization of Crab Waste for Cost-Effective Bioproduction of Prodigiosin

“…Our previous studies revealed that the salt composition, including sulfate and phosphate salts, demonstrate a significant effect on PG production using S. marcescens [11,[30][31][32] (Figure 3).…”

“…A review of the recent literatures found that numerous studies have reported on PG production. However, in most previous studies, PG production was conducted in a minor scale (in flasks) using commercial nutrients as C/N sources for fermentation [11]. Different to previous research, our study successfully engaged in cost-effective PG production at a large scale (a 15 L bioreactor system) using low-cost material (crab waste) as the C/N source for fermentation.…”

“…Of these, the ABTS radical scavenging activity of the PG was higher than the DPPH radical scavenging capacity of the PG, with a max activity of 98.3% (at a tested PG concentration of 4 mg/mL) and 96% (at a tested PG concentration of 8 mg/mL), respectively. To provide more clarity, the IC 50 values (the concentration of an antioxidant compound that may reduce 50% of the radical scavenging [11]) of the ABTS and DPPH radical scavenging activity of the PG were also expressed as 1.25 mg/mL and 2.64 mg/mL, respectively. The α-tocopherol, a standard antioxidant compound was tested for the comparison activity and showing its ABTS and DPPH radical scavenging activity of 13.3 µg/mL and 23.1 µg/mL, respectively.…”

“…In this study, we investigated the use of crab shells for the production of the active medical compound prodigiosin. Recently, the study of PG has been renewed and increased due to its beneficial effects, especially its high anticancer activity [11,13] and lack of toxicity to normal cells [11]. To enhance the anticancer effect, PG was combined with other agents [14], formed nanoparticle sizes [15], and synthesized its derivatives [16].…”

“…For the green production of PG, under the considerations of environmental problems and low-cost production, we established the utilization of marine chitin-containing wastes for the production of PG [11,[29][30][31]. These previous studies focused on reusing squid pens as a C/N source for the production of PG via fermentation by S. marcescens TKU011 [29][30][31] and S. marcescens TNU01 [11]. Recently, we found that the addition of chitin to the medium has a significant effect on enhancing PG yield in the culture broth and that α-chitin (extracted from crab shells) has a better effect compared to β-chitin (extracted from squid pens) [32].…”