Replacement of acetic acid with ammonium acetate boosts triacylglycerol productivity without significant growth retardation in the green alga Chlamydomonas reinhardtii

Abstract

Microalgal cultivation is one of the main factors restricting biomass production as well as energy fuel production. It is widely known that nitrogen starvation condition triggers triacylglycerol accumulation in many green algae. Yet, such a condition suppresses growth of the algae. It is of our interest to develop culture conditions and cultivation systems for TAGs induction that does not hamper growth. We report in this study that the substitution of acetic acid with ammonium acetate in the modified TAP medium could trigger significant amount of TAG in Chlamydomonas reinhardtii while not drastically reducing growth. Application of ammonium acetate in semi-continuous cultivation showed that microalgal growth and TAG productivity could be maintained for up to 5 rounds. This finding could lead to further studies and optimizations to apply ammonium acetate for microalgal cultivation for TAG production.