Developing Serum-Free Media Via Bioprocessing For Cultivated Seafood Products

Global food production management has become a challenge with an anticipated population of 10 billion people by 2050 and the ongoing COVID-19 epidemic. Seafood is a vital food source due to its widespread consumption, excellent nutrient profile, and low feed conversion ratio, rendering its sustainable production quintessential. Cellular agriculture or cultured meat can increase seafood production; however, the conventional use of Fetal Bovine Serum (FBS) in culture media restricts its utilization at an industrial level. FBS is effective but has many limitations: unethical animal extraction, high demand and low supply, poorly defined ingredients, variable performance, and high cost that impedes the feasibility and commercial viability of cellular agriculture. Thus, employing serum-free media becomes a quintessential need for cellular agriculture. This project aims to replace or reduce the typical 10% serum usage in Zebrafish embryonic stem cell (ESC) production media with protein hydrolysates derived from low-cost natural sources with high protein content. Enzymatic hydrolysis was performed on nine sources: insects (black army fly and cricket), plants (pea), fungi (mushroom and yeast), algae, and marine invertebrates (oyster, mussel, and lugworm). The resulting hydrolysates were evaluated for serum replacement in zebrafish ESCs. All hydrolysates were used at five different concentrations (10, 1 0.1, 0.01 and 0.001 mg/mL) in serum concentrations of 10%, 5%, and 0% with four biological replicates. The best hydrolysate sources and concentrations were selected for further testing at 2.5% and 1% serum concentrations. All hydrolysates, except for cricket, could restore or significantly increase cell growth with 50% less serum at a concentration of 0.1-0.001mg/mL. Protein hydrolysate concentration of 10 and 1mg/mL was toxic for cells. Additionally, the eight hydrolysates could reduce serum concentrations up to 75–90%. However, no protein hydrolysate could completely replace serum, as cells using only protein hydrolysates exhibited morphological aberrations and decreased growth. Replacing serum with protein hydrolysates lowers cellular agriculture's overall cost, thus enabling the commercialization of cultured meat and the development of a sustainable food system. In the future, blending various protein hydrolysate sources with or without the addition of conventional growth factors could be done to create the ideal serum-free media.