Use of Palm Oil Mill Effluent as Medium for Cultivation of Chlorella sorokiniana

Aims: Palm oil mill effluent (POME) erodes the principal biophysical characteristic of both soil and water when discharged untreated but could be exploited as medium for microalgae cultivation due to its vast mineral contents.

Place and Duration of study: POME samples were collected from a local palm oil processing mill at Nsukka, Enugu State, Nigeria. A part of the study was done at the Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan while the rest at the University of Nigeria, Nsukka between March and September, 2012.

Methodology: Chlorella sorokiniana C212 was grown in several Batches (A-D) of POME supplemented with urea (60 mg/L) before subjecting to different sterilization protocols. Cultivation was conducted in shaker flasks at 150 rpm, 1 vvm, 3000 lux and pH 7.0±0.2.

Results: The filter sterilized Batch (B) promoted the highest (1070±30 mg/L) dry cell weight (DCW), lipid (156±12 mg/g-cell) and chlorophyll (1.59±0.11 mg/g-cell) contents while chemical oxygen demand (COD) decreased by 45±08%. The autoclaved medium (Batch A) gave the least DCW (310±20 mg/L), lipid production (40±05 mg/g-cell) and chlorophyll content (0.58±0.02 mg/g-cell) while COD reduced by 20±04%. The highest COD decrease (70±05%) was achieved in the unsterilized Batch (D). Batch B was most positively affected by dilution because at 75% concentration, DCW increased to 1360±30 mg/L, lipid contents to 174±10 mg/g-cell, chlorophyll to 1.87±0.14 mg/g-cell the while COD declined by 63±03%.

Conclusions: POME has potential for use in microalgae cultivation with significant saving in treatment costs.