A holistic approach to managing palm oil mill effluent (POME): biotechnological advances in the sustainable reuse of POME.

The demand for cellulases has increased tremendously over the last few decades. This is due to its numerous applications in industry and also because it can be used to hydrolyze cellulosic materials into sugars that can be fermented into bioethanol and bio-based products. This does not only open up a big and significant market for cellulases, but also provides another source of biofuel and bioenergy in the future. Nevertheless, the cost of the existing substrates for cellulase fermentation is very high if required for large-scale production. Sustainable supplies and an economically feasible biomass are needed to reduce the cost of cellulase production. Palm oil mill effluent (POME) is rich in carbohydrates, proteins, nitrogenous compounds, lipids, minerals, cellulose, hemicelluloses and lignin. It can be used naturally as a fermentation medium, either for cellulase or other value-added product fermentation. In Malaysia, a large and continually increasing amount of POME is produced every year because of the high global demand for palm oil. Hence, the development of cellulase production from POME is reviewed, covering the POME production, cellulase production and the major challenges together with the future prospects of these processes.

Cellulase production from palm oil mill effluent in Malaysia: Economical and technical perspectives

The filamentous fungus Trichoderma harzianum was used for liquid state bioconversion of POME for cellulase production. Statistical optimization was carried out to evaluate the physico-chemical parameters (factors) for maximum cellulase production by 2-level fractional factorial design with six central points. The polynomial regression model was developed using the experimental data including the effects of linear, quadratic and interaction of the factors. The factors involved were substrate (POME) and co-substrate (wheat flour) concentrations, temperature, pH, inoculum and agitation. Statistical analysis showed that the optimum conditions were: temperature of 300C, substrate concentration of 2%, wheat flour concentration of 3%, pH of 4, inoculum of 3% and agitation of 200 rpm. Under these conditions, the model predicted the enzyme production to be about 14 FPU/ml. Analysis of variance (ANOVA) of the design showed a high coefficient of determination (R2) value of 0.99, thus ensuring a high satisfactory adjustment of the quadratic model with the experimental data.

Ahmad Fadhlan Hamisan

Papers

Liquid state bioconversion of palm oil mill effluent for cellulase production: statistical optimization of process conditions