Pigment production by Scenedesmus dimorphus using different low-cost and alternative culture media

BACKGROUND This study investigated the feasibility of producing pigments from Scenedesmus dimorphus using different low-cost synthetic and alternative media. Thus the influence of nitrogen and phosphorus deficiency, different nitrogen sources and alternative culture media (wheat bran, garlic powder, wheat bran supplemented with garlic powder) on pigment and biomass production was evaluated. RESULTS Among the three sources of nitrogen studied (ammonium sulfate, urea and sodium nitrate), urea was the cheapest efficient alternative source of nitrogen for pigment production, especially total chlorophylls (67.38 mu g L-1 d(-1)), by this strain, without strongly affecting biomass yield. Phosphorus deficiency had no negative effect on biomass production, but improved the production of zeaxanthin and chlorophyll b by13.1% and 26.8%, respectively, compared to control. Compared to BG-11 medium, the alternative garlic powder medium increased the biomass yield of S. dimorphus by 5.2 times, improved the productivity of xanthophylls and contributed to the accumulation of beta-carotene. Wheat bran medium was found to be efficient as a zero-cost culture medium for the production of pigments, where S. dimorphus accumulated twice the total pigment concentration of the control, with high beta-carotene productivity (38.58 +/- 11.94 mu g L-1 d(-1)). The addition of garlic powder to wheat bran increased the biomass (3.14 g L-1) and pigment productivity (216.86 +/- 2.06 mu g L-1 d(-1)) by 28.5 and 1.4 times, respectively, but inhibited zeaxanthin biosynthesis. This alternative medium reduced biomass and pigment production costs by 99.80% and 96.21%, respectively. CONCLUSION Wheat bran supplemented with garlic powder showed good application potential for the industrial production of biomass and pigments from S. dimorphus in open cultivation systems where garlic powder might be used simultaneously for biomass and pigment accumulation, and for biological contamination control. (c) 2021 Society of Chemical Industry (SCI).