Production of safe cyanobacterial biomass for animal feed using wastewater and drinking water treatment residuals.
Seonghwan Park, Sang-Jun Lee, Won Noh, Yeong Jin Kim, Je-Hein Kim, Seng-Min Back, Byung-Gon Ryu, Seung Won Nam, Seong-Hoon Park, Jungmin Kim
Author Information
Seonghwan Park: Biomass Research Group, Gyeongnam Branch Institute, Korea Institute of Toxicology, Jinju, 52834, Republic of Korea.
Sang-Jun Lee: Biomass Research Group, Gyeongnam Branch Institute, Korea Institute of Toxicology, Jinju, 52834, Republic of Korea.
Won Noh: Biomass Research Group, Gyeongnam Branch Institute, Korea Institute of Toxicology, Jinju, 52834, Republic of Korea.
Yeong Jin Kim: Environmental Safety-Assessment Center, Gyeongnam Branch Institute, Korea Institute of Toxicology, Jinju, 52834, Republic of Korea.
Je-Hein Kim: Human Risk Assessment Center, Jeonbuk Branch Institute, Korea Institute of Toxicology, Jeongeup, 56212, Republic of Korea.
Seng-Min Back: Genetic & Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea.
Byung-Gon Ryu: Microbial Research Department, Nakdonggang National Institute of Biological Resources, Sangju, 37242, Republic of Korea.
Seung Won Nam: Bioresources Collection & Bioinformation Department, Nakdonggang National Institute of Biological Resources, Sangju, 37242, Republic of Korea.
Seong-Hoon Park: Genetic & Epigenetic Toxicology Research Group, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea.
Jungmin Kim: Biomass Research Group, Gyeongnam Branch Institute, Korea Institute of Toxicology, Jinju, 52834, Republic of Korea.
The growing interest in microalgae and cyanobacteria biomass as an alternative to traditional animal feed is hindered by high production costs. Using wastewater (WW) as a cultivation medium could offer a solution, but this approach risks introducing harmful substances into the biomass, leading to significant safety concerns. In this study, we addressed these challenges by selectively extracting nitrates and phosphates from WW using drinking water treatment residuals (DWTR) and chitosan. This method achieved peak adsorption capacities of 4.4 mg/g for nitrate and 6.1 mg/g for phosphate with a 2.5 wt% chitosan blend combined with DWTR-nitrogen. Subsequently, these extracted nutrients were employed to cultivate , yielding a biomass productivity rate of 0.15 g/L/d, which is comparable to rates achieved with commercial nutrients. By substituting commercial nutrients with nitrate and phosphate from WW, we can achieve a 18 % reduction in the culture medium cost. While the cultivated biomass was initially nitrogen-deficient due to low nitrate levels, it proved to be protein-rich, accounting for 50 % of its dry weight, and contained a high concentration of free amino acids (1260 mg/g), encompassing all essential amino acids. Both in vitro and in vivo toxicity tests affirmed the biomass's safety for use as an animal feed component. Future research should aim to enhance the economic feasibility of this alternative feed source by developing efficient adsorbents, utilizing cost-effective reagents, and implementing nutrient reuse strategies in spent mediums.
