Enhancing starch accumulation/production in Chlorococcum humicola through sulphur limitation and 2,4- D treatment for butanol production

Depleting fuel resources is a global concern worldwide due to the unstable and cost of fuel resources. Increased transportation has gradually depleted the fossil-based fuel resources leading to find a cost-effective, readily available, and renewable source. Considering these issues, various private and government organizations have focussed on producing bio-based fuels from natural sources. In this scenario, algae are a potential emerging source of feedstock or biomass for biobutanol production, which can effectively replace fossil fuels and their environmental drawbacks. The present study focussed on evaluating the potential of freshwater microalga Chlorococcum humicola isolated from temple pond as feedstock for biobutanol production using Clostridium acetobutylicum. The results indicated that C. humicola produced 846.33 μgmg−1of starch under full strength Chu10 medium. While under sulphur and phosphorus limitation, the accumulation of starch was 947.33 μg mg−1 and 766.67 μgmg−1, respectively. Also, C. humicola was exposed to different concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D). At 10μgml−1 of 2,4-D, the highest starch concentration of 989μgmg−1was achieved in C. humicola. Finally, starch in C. humicola were hydrolysed and ABE fermentation was performed using C. acetobutylicum under anaerobic condition in a 5 L automated fermenter. After 72 h of fermentation, the fermented broth is analyed in Gas Chromatography showing the fermented product containing Acetone: Butanol: Ethanol. The present study is the first report on the production of biobutanol from C. humicola isolated from Temple pond. This study emphasizes the importance of local isolates of microalgae as a third-generation substrate to produce butanol to replace fossil-based fuels.