Temperature and photoperiods optimization for the cultivation of Chlorella vulgaris for growth and biomass production from cassava wastes

Abstract

Microalgae biomass is widely being used as a third generation biofuel because they are the most promising renewable feedstock for biofuel production. Its use is greatly considered as it has high growth rate, photosynthetic efficient, not competing for arable land, efficient carbon dioxide fixation and potential to accumulate high amount of carbohydrate. Microalgae carbohydrates are contained in their cell wall mainly as cellulose and plastids as starch which are readily converted into fermentable sugars. The cultivation of Chlorella vulgaris on cassava wastes for growth and biomass production depends on factors such as temperature and photoperiods. Cassava waste mixtures were cultivated on Chlorella vulgaris stock culture at different concentration ratio at pH of 6.5 and salinity of 10mg/l, cultivation ratio of 160:40 for cassava peel water to cassava waste water CP:CW at 670nm absorbance for 7 days. Temperature variations of 200C, 300C and 350C were checked to determine the optimum temperature for the growth and biomass production of Chlorella vulgaris on the optimum cassava waste mixture concentration. Photoperiod variation of 12:12, 6:18 and 18:6 were checked to determine optimum photoperiod for the growth and biomass production of Chlorella vulgaris on the optimum cassava waste mixture concentration. From the results obtained in this optimization study, optimum growth and biomass was recorded at temperature of 30 ℃. Photoperiod of 12:12 was responsible for optimum growth while photoperiod of 18:6 light and dark conditions gave high biomass production. This study shows that optimized conditions are necessary high growth and biomass production of the microalgae on cassava waste.