A culture method for microalgal forms using two-tier vessel providing carbon-dioxide environment: studies on growth and carotenoid production

Abstract

A culture method was developed for photoautotrophic culture of Haematococcus pluvialis, Chlorella vulgaris, Scenedesmus obliquus, Spirulina platensis, Nostoc and Stigonema in a two-tier flask consisting of nutrient media in the upper chamber and CO2 generating buffer mixture (KHCO3/K2CO3) in the lower chamber. The concentration of buffer mixture was varied to obtain desired levels of CO2. CO2 at 2.0% (v/v) level enhanced growth and chlorophyll content over control cultures (without CO2 supplementation) in all microalgal species. Haematococcus pluvialis culture in BBM and KM1 media showed 6.71- and 2.07-fold increase in biomass yields with astaxanthin productivity at 7.26 and 7.48 mg l−1 level respectively. CO2 supplementation to C. vulgaris and S. obliquus cultures resulted in 5.97- and 7.30-folds increase in biomass with 2–3 fold increase in chlorophyll and carotenoid contents over their respective controls. Similarly 2–3 fold increase in chlorophyll and carotenoid contents were observed in Sp. platensis, Nostoc and Stigonema spp. This culture methodology will provide information on CO2 requirement for growth of algae and metabolite production and also facilitates studies on the influence of light and temperature conditions.