Nipa (Nypa fruticans) sap as a potential feedstock for ethanol production

The current study was initiated to evaluate the potential of sugar saps from nipa (Nypa fruticans) palm as sustainable feedstock for ethanol production. Nipa palms managed as plantations on four sites was chosen for this study with palms within 8-100 years of age. All palms studied were found to have the potential to produce sugar saps from 0.4 to 1.2 L d-1 per palm. Further chemical characterization of its saps gave a total composition of 159-214 g kg-1 mainly composed of sucrose, glucose and fructose. In addition, the elemental analysis gave 5 g kg-1 of inorganics with Na, K and Cl being its main inorganic elements. Preliminary batch fermentative assays using Saccharomyces cerevisiae showed that nipa saps can be converted to ethanol within 30-48 h in conditions with and without nutrient supplementation. Furthermore, the fermentation trends were similar to sugarcane sap with high ethanol conversions up to 96.9% and 95.5% achieved for both nutrient conditions. Further analysis on inorganic elements before and after fermentation showed that specific elements of Mg, Ca, P and S were significantly reduced and could have assisted the fermentation. Based on the results obtained from sap collection, chemical characterization and fermentation, the ethanol potential from nipa planted at a density of 1000 ha-1 would range from 4550-9100 L ha-1 y-1. Conclusively, nipa sap showed some interesting characteristics which makes it a potential feedstock for ethanol production.