Impact of cultivation conditions on microalgae biomass productivity and lipid content

Abstract

Microalgae is a third-generation renewable source of biofuels (bio-oil, biodiesel, bioethanol, biomethane, etc.), which has allured significant interest worldwide. Biodiesel produced from microalgae is strong substitute for conventional diesel as it is a carbon–neutral fuel which can overcome limitations of first- and second-generation biofuel. Microalgae being a photosynthetic organism can be cultivated in Open (Ponds) and Close (Photobioreactor) cultivation system. Photobioreactors provide better control over cultivation parameters and needs to be developed for maximum production, cost effectiveness, low maintenance, etc. Large variety of the microalgae strain with varying lipid content is present and selection of microalgae strain is crucial for biodiesel quality as lipid is main biomass that is converted into biodiesel. The main objective of this research work is to reviews the salient features and limitations of developed photobioreactors and the impact of different cultivation conditions such as light intensity, light colour, temperature, pH etc. on lipid content and biomass productivity of microalgae for biodiesel production. This study reveals the optimum range for bioenvironmental conditions (Light, Temperature, pH) for maximum growth and lipid content for the various microalgae species. Among different photobioreactors it is suggested that closed system (photobioreactor) is more efficient at producing microalgae while hybrid type photobioreactors needs to be developed in such a way that it can overcome shortcomings of the developed photobioreactor.