Optimum Conditions for Cultivation of Chlorella vulgaris on Oil Palm Residue Extracts

Abstract

The need to manage agro waste in the environment has continued to generate worries to most developing countries. Oil palm mill waste cause pollutions of soil, water and environment but could be exploited as substrate for algal growth because of its rich mineral and carbohydrate contents. In this study Oil palm cake and Empty fruit bunch residue were obtained from Aluu, Rivers State Nigeria. The proximate, physicochemical analysis of the extract were ascertained, wavelength selection of extract was done to monitor for biomass production, growth media ratio of extract and One Factor at a Time (OFAT) was employed for the optimization of Chlorella vulgaris growth on the Oil Palm Residue Extracts. The proximate result revealed that the range of Ash (8.40 ± 0.30 - 6.60 ± 0.40 ppm), Moisture (10.90 ± 0.30 - 6.75 ± 0.65 ppm), Lipid (22.05 ± 0.35 - 14.90 ± 0.30 ppm), Protein (1.30 ± 0.18 - 0.80 ± 0.08 ppm), Fiber (25.50 ± 0.50 - 39.09 ± 0.57 ppm) and Carbohydrate (29.83 ± 0.29 - 29.29 ± 0.58 ppm). The physicochemical composition pH (5.15 ± 0.02 - 5.36 ± 0.06), Conductivity (224.15 ± 0.45 - 481.00 ± 2.00 µS/cm), DO (2.87 ± 0.06 - 4.86 ± 0.06 ppm), Nitrate (31.05 ± 0.48 - 40.33 ± 0.98 ppm), Sulphate (36.35 ± 0.46 - 50.68 ± 0.49 ppm) and phosphate (27.71 ± 0.50 - 37.35 ± 0.55 ppm) were obtained for Oil palm cake and Empty fruit bunch respectively. Wavelength of 620 nm exhibited better accuracy for the biomass monitoring and optimization investigations. Growth media ratio selected was 180:20 for empty fruit bunch: oil palm cake. The optimization revealed pH 6.0, temperature 30oC, salinity 10ppm and photoperiod 12:12 day: night as optimal condition for the growth of Chlorella vulgaris biomass. The oil palm residue can be a veritable medium for growth of this algae and biotechnological application in waste management.