Mixotrophic Cultivation Of Microalgae: An Alternative To Produce High-Value Metabolites

Microalgae are important sources of biotechnological products, including pigments, lipids, polyunsaturated fatty acids, polysaccharides, vitamins, and other bioactive compounds. These microorganisms are photosynthetic; however, under photosynthetic growth conditions, biomass and metabolite production can be limited by light availability. An alternative is mixotrophic microalgae growth, based on the addition of organic carbon sources (i. e. carbohydrates, organic acids, alcohols, etc.) in the presence of light. It has been documented that, in contrast to the cultivations conducted under autotrophic conditions, the cultivation of several species of microalgae under mixotrophic conditions generally showed improvements in growth rates, biomass, and high-value compound concentrations. This review is focused on those studies recently published in relation to the mixotrophic growth of microalgae as an alternative method of producing high-value products (PUFAs, pigments, polysaccharides, vitamins and peptides), emphasizing those species that grow mixotrophically. Additionally, bioengineering and metabolic engineering strategies developed to improve mixotrophic growth and metabolite production, are discussed.