Growth responses of Chlorella sp. to some selected variants of culture medium and in effluents of a Brewery

Abstract:

Global  warming  poses  a  major  threat  to our  civilization  that  has  led to unsustainable development   worldwide.   Though   there  are  different   strategies   for  global   warming mitigation, carbon sequestration in water column via microalgae is the eco-friendly, cost effective and sustainable tool to capture and utilize carbon in a beneficial way. Microalgae, Chlorella sp. was cultured in ex situ using (a) standard basal medium as control, (b) culture medium aerated, (c) exogenously introduced liquid carbon dioxide into the culture medium. The growth of Chlorella was also examined under different pH (4 - 11) of the culture medium as well  as in various  dilutions (0,  25,  50%)  of effluents  of a Brewery under autoclaved and non- autoclaved conditions. There was no marked difference in growth of Chlorella sp. between 0 - 166 hours and between 218 - 272 hours either, but significant difference (P < 0.05) in growth was clearly discernable during the peak period among the treatments. Exogenously introduced CO2 or aeration of the culture medium did not significantly improve the growth over basal medium suggesting that optimal conditions of carbon  or  oxygen  have  prevailed  in  the  basal  medium  of culture.  There  was a  sharp dichotomy of pH effects on the growth of Chlorella as growth was distinctly higher at pH 8 to 11 compared to the remaining pH (4 - 6) showing no significant differences (P > 0.05) among themselves. Chlorella sp. grown in brewery effluent showed the maximum growth in 50% and 25% dilution of non autoclaved and autoclaved effluent of beverage factory respectively suggesting that autoclaving saved 25% of bacteria driven nutrient demand.