Strategic enhancement of algal biomass and lipid in Chlorococcum infusionum as bioenergy feedstock

Algal biomass can serve as rich source of bioproducts including lipids for diverse commercial applications. Both biomass production and lipid accumulation are limited by several factors, of which nutrients play a vital role. In the present investigation, the nutritional requirement for the growth by a (an autotrophic) Chlorococcum infusionum was determined using a Plackett-Burman based statistical screening experiment. Five out of the fifteen factors of a reported production medium were found to be significantly affecting the biomass growth. The components NaNO3, K2HPO4, FeSO4.7H(2)O and KOH had direct proportional correlation with biomass production, while MgSO4 showed inverse proportional relationship in the selected experimental range. Nitrogen was the most influential factor with an effect contribution of 45.77% and a very low p-value of <0.001. The most favorable nitrogen source was potassium nitrate which could replace both sodium nitrate and potassium hydroxide. More than two fold increase in biomass concentration was achieved by screening and standardizing the media components of Bold Basal Medium. Lipid accumulation under normal condition was 12-15% dry cell weight (dcw). Under nitrogen starvation condition, it was 30-35% dcw. However, a semi-starvation condition at 1.75 mM of sodium nitrate induced lipid production as high as 40 +/- 2% dcw. FAME analysis in GC showed the presence of more saturated fatty acids. Results obtained in this work can further be applied to optimize production of algal biomass and lipid for applications like biofuel, fish or animal feed, fertilizer, etc. Also information obtained could be exploited forwastewater treatment processes. (C) 2013 Elsevier B.V. All rights reserved.