Recycling spent animal cell culture media using the thermally resistant microalga Chlorella sorokiniana

Abstract

Cell culture media is a significant contributor to the high cost of bioprocesses. This study explored the potential of algae to re-condition spent cell culture medium, which may reduce the costs of pharmaceutical and lab-grown-meat manufacturing. Chlorella sorokiniana, a thermally resistant microalgal species, exhibited heterotrophic and mixotrophic growth in mammalian cell culture growth media (GM). Spent animal cell media, generated by culturing quail myoblast cells (QM7s) for 4 or 8d (4D-SGM and 8D-SGM, respectively), was harvested for algal culture. Increased algal growth was observed in 4D-SGM, when compared to fresh media after 3d (optical density of 1.39 ± 0.22, 0.47 ± 0.17, p ≤ 0.05). Within 72 h, ammonia and glucose were eliminated from 4D-SGM with algal treatment. After treating 4D-SGM with algae, the treated media was reintroduced into QM7 cell cultures. No cytotoxic effects were observed on QM7 cells grown in algal-treated growth media and QM7 cells exhibited better metabolic activity in algal-treated spent medium than in untreated spent medium (80.85 ± 12.02% and 44.57 ± 10.82% activity of fresh media group, respectively, p ≤ 0.05). These results suggest that C. sorokiniana can be grown in spent media at 37 °C, sequester ammonia, and potentially extend the lifespan of media, thereby enabling more affordable bioprocesses.