PhotoBiobox: A tablet sized, low-cost, high throughput photobioreactor for microalgal screening and culture optimization for growth, lipid content and CO2 sequestration

Abstract

Microbial screening and culture optimization is a laborious, multifaceted and expensive procedure often taking years and millions to identify the ideal strain for specific use. In this study, a high throughput, tablet-sized, low cost photobioreactor, herein referred as "PhotoBiobox", was fabricated and tested for screening and culture optimization of microalgae suitable for biomass and biodiesel production, and CO2 sequestration. PhotoBiobox is equipped with a LED array and photo gradient filter offering different light intensities. PhotoBiobox was fabricated to screen and cultivate several microbial strains in 96-well plate in wide temperature range and CO2 atmosphere. To test its efficacy, a total of 12 microalgal strains were isolated from Korean freshwaters, identified and screened for high growth and lipid accumulation potential. Among the 12 strains, Parachlorella sp., JD076 showed highest growth rate, remarkable stability and tolerance to different temperature regimes. Optimization experiments using PhotoBiobox revealed that this strain had optimum temperature range and light intensity of 24-25°C and 400μmolm-2s-1, respectively, with high growth rate and lipid content in 5% CO2 condition. The screening and optimization of culture conditions using PhotoBiobox took just 15 days, in total, which could radically reduce both screening costs and time. PhotoBiobox can be used as a screening and optimization reactor in several areas of microbiology and cell biology, while serving as a prototype for furthering research on miniaturization in this field.