Optimization of Parachlorella kessleri Growth under Different Environmental Conditions for Lipid Production

Abstract The sustainable development of polymers and biofuels through photosynthetic biomass cultivation has become a growing global priority driven by environmentally green procedures. The unicellular green algae Parachlorella kessleri has shown potential for lipid and biopolymer production. In this study, a P. kessleri strain (PDP-01) was isolated from the Yamuna River in Delhi. The organism was cultured and characterized using morphological, biochemical and molecular techniques for identification. This study was performed to examine the influence of media pH, incubation temperature, photoperiod, and CO 2 concentration on the growth characteristics of P. kessleri . A one-factor-at-one-time approach was used to assess the effect of parameters on cell reproduction. Lipid and polyhydroxyalkanoate (PHA) content was additionally quantified from biomass. The findings indicated that the maximum biomass production occurred in a 16-day-old culture under the following conditions: pH 8, a temperature of 25°C, a photoperiod of 16:8 (light:dark), and 2% CO 2 concentration. Under these conditions, the strain accumulated 17% lipid and 11% PHA of dry cell weight demonstrating its dual potential for lipid and biopolymer co-production. To our knowledge, this is the first report of an indigenous P. kessleri isolate from the Yamuna river, Delhi characterized and optimized for biomass, lipid and PHA production, highlighting it’s biorefinery potential for sustainable bioplastic application.