RESUMEN
Aims@#A study on biosorption ability using encapsulated endophytic fungi has been carried out to investigate its biosorption potential in removing heavy metals. Biosorption has emerged as an alternative bioremediation process to remove and sequester heavy metal ions from polluted water. An endophytic Pestalotiopsis sp. (isolated from Nypa fruticans) was found to be able to resist copper (Cu), chromium (Cr), lead (Pb) and zinc (Zn) up to 1,000 ppm and thus the aim of this study was to investigate the biosorption ability using encapsulated live and dead Pestalotiopsis sp. biomass (at pH 4-6) to remove heavy metals. Additionally, a proteomic study was conducted to investigate down- and up-regulation expression levels of proteins under the treatment of the heavy metals. @*Methodology and results@#Encapsulated live fungal biomass displayed higher efficiency in removing chromium at pH 5 and 6, while both encapsulated live and dead biomass were able to remove lead at pH 4 and 5 and copper at pH 5. Five (5) proteins of interest were identified via MALDI-ToF analysis. Among the proteins identified, multidrug resistance protein (MRP homolog) was up-regulated in the presence of lead. @*Conclusion, significance and impact of study@#The data obtained in this study provides an initial understanding of the biosorptive and defensive mechanisms of Pestalotiopsis sp. under heavy metal stress.
RESUMEN
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.