ABSTRACT
Aims: Palm oil mill effluent (POME) is a major agricultural waste product of Malaysia. The aim of this study was to identify endophytic fungi capable of producing biofuel feedstock utilizing POME. Methodology and results: Endophytes were isolated from the Nipah palm tree, Nypa fruticans, and exposed to different POME concentrations (25%, 50% and 75%), with and without the addition of nutrients. The utilization of glucose was measured using the Dinitrosalicylic Acid assay whereas the lipid content in the fungal cells was extracted using the Bligh and Dyer method with slight modifications. Three endophytic fungi that displayed the highest growth on POME were identified using ITS 1 and 4 primers and found to be related to Pestalotiopsis sp., Lasiodiplodia theobromae and Rhizoctonia bataticola. Nutrient addition caused an average increase of 8 times in biomass, indicating nitrogen requirement for cell proliferation. The highest POME concentration (75%) resulted in lower biomass yield. Furthermore, all fungal samples in high POME concentration and nutrient conditions showed a decrease in lipids accumulated per milligram of biomass whereby lipid synthesis was enhanced under nitrogen limitation (25% without nutrients). Conclusion, significance and impact of study: In conclusion, all fungal samples can be classified as oleaginous microorganisms with Pestalotipsis sp. being the most efficient (up to 70% of its biomass). This is to our knowledge the first study that shows the potential use of Pestalotiopsis sp., L. theobromae and R. bataticola for the utilisation of POME as biofuel feedstock and could in the future potentially provide an alternative approach to the treatment of POME with value-added effect.
ABSTRACT
Aims: Waste electric and electronic equipment (WEEE) are among the fastest growing waste products worldwide and solutions to their remediation are urgently needed. Bioremediation is a green approach that is helpful to minimize environmental pollution associated with Electronic waste (E-waste). The present study aimed at exploring the potential of endophytic fungi from Nepenthes ampullaria for bioremediation purposes of the plastic component in E-waste, polyurethane (PUR) polymers. Methodology and results: Endophytic fungal isolates were assessed for their ability to degrade PUR as well as their ability to utilise PUR as sole carbon source. Nine (9) out of 150 isolates demonstrated the ability to efficiently degrade polyurethane in solid medium and the top three (3) isolates were able to grow on PUR as the only carbon source. These three isolates were identified using ITS1 and ITS4 and found to be closely related to the genus Pestalotiopsis. The top two of the three isolates were then assessed for their esterase enzyme activity as well as changes in their proteome when grown with and without PUR. The highest enzymatic activity was found to be 1850.4 U/mL when tested using pnitrophenol acetate as the substrate. Analyses of the 2-dimensional electrophoresis profile revealed changes in the abundance of proteins when treated with polyurethane. Conclusion, significance and impact of study: This study is to our knowledge the first on endophytes isolated from N. ampullaria that can degrade PUR, and also their proteomes. Results obtained from this study can in the future help to reduce polyurethane wastes. Besides degrading PUR polymer, endophytic fungi produce potential valuable proteins that may find broad applications in bioremediation applications.