Microalgae for industry: Responses of native Australian chlorophytes to environmental conditions for enhanced production of target compounds

Microalgae produce a range of metabolites such as proteins, lipids and fatty acids, pigments such as chlorophyll and carotenoids, and almost all essential vitamins. These have a wide variety of applications including health supplements, antioxidants, cosmetics, aquaculture, animal feed and biofuel production. Microalgae are fast-growing, may be easy to cultivate, may persist even in harsh conditions and are ubiquitous across all ecosystems on earth. They are therefore excellent candidates for commercial exploitation. This study focuses on two major groups of microalgal metabolites: lipids and pigments. Various environmental factors can significantly alter growth and metabolite production of microalgae including temperature, pH and nutrient and light availability. Further, the effects of these parameters on algae vary widely across species and even strains. The industry of cultivating microalgae relies on cost minimisation and product maximisation to achieve financial viability. Optimisation of production in terms of species/strain selection and growth conditions is imperative to sustainable and cost-effective production. In this study, native Australian chlorophytic microalgae were grown under various conditions to determine their suitability to mass production. Desmodesmus opoliensis CS-904 and Chlorella vulgaris CS-41 were sourced from the Australian National Algae Culture Collection at the Commonwealth Scientific and Industrial Research Organisation (CSIRO)