Heterotrophic and Mixotrophic Cultivation of Chlorella vulgaris using Chicken Waste Compost as Nutrients Source for Lipid Production

Microalgae have received global attention for the past decades as it shows promising results to be an alternative and sustainable energy resource due to their high growth rate and lipid production. In commercial microalgae cultivation, autotrophic method is always used to grow the microalgae. However, this method usually produces high biomass yield but low lipid content. One of the approaches to enhance the microalgae lipid yield is through heterotrophic and mixotrophic method, in which dark environment and organic carbon are introduced as a stress factor to induce the lipid productivity. In the present study, cultivations of microalgae were done using chicken compost and glucose under autotrophic, heterotrophic and mixotrophic conditions. The highest absorbance attained for both heterotrophic and mixotrophic cultivation conditions were 1.650 and 2.184 respectively when 1.0 g/L of glucose was used. Absorbance and biomass are correlated, therefore the absorbance in this study signifies the amount of biomass produced. Moreover, the highest lipid yield was successfully attained at 45 wt% under mixotrophic condition. Overall, the lipid yield of microalgae cultivated under mixotrophic was higher than the heterotrophic condition when compost derived from chicken waste was used as nutrients source.