UV radiation as a new tool to control microalgal bio-product yield and quality : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Industrial Biotechnology at Massey University, Palmerston North, New Zealand

Abstract

While ultraviolet (UV) radiation is most commonly known as an abiotic stress, various studies have shown targeted UV exposure increases bioproduct and biomass yields in microalgae. Microalgal cultivation processes face significant limitations in achievable bioproduct and biomass yields and thus improvements offered by targeted UV treatments during large-scale microalgae cultivation provide an opportunity for development of a novel UV treatment tool. Growing demand in microalgae (bio)products indicate there may be a substantial market for such UV treatment tools. No initiatives that explore the development of targeted UV treatments during large-scale microalgae cultivation have been found in the literature or in the industry. In collaboration with industrial partner BioLumic, a company specializing in applying targeted UV treatments in plants as a tool in agriculture, this PhD research examined if specific treatments of UV radiation (i.e. specific in UV waveband, irradiance and exposure duration) can reliably increase carotenoid accumulation in the microalga Dunaliella salina and if this new understanding can be feasibly used to develop an industrial system for UV treatment of microalgae.