Study Of Stability Alginate-Is258 (Nakasoemyces Glabrata) Matrices Reinforced With Polyvinyl Alcohol For The Production Of Bioethanol From Coconut Sap Analog Media

Abstract

The growing demand for energy is driving the development of environmentally friendly alternative energy sources, one of which is bioethanol. Bioethanol can be produced through the fermentation of sugar using yeast to produce alcohol; immobilized IS258 can be used for this process. This study aims to determine the stability of the polyvinyl alcohol-reinforced alginate-IS258 matrix (Alg-PVA-IS258), assess its service life, and determine the amount of bioethanol produced using Alg-PVA-IS258. This study is a descriptive experimental study with four PVA concentrations (0.5%, 1%, 1.5%, and 2% (w/v)), each with three replicates per treatment, using a fed-batch system over eight fermentation cycles. The parameters observed included total ethanol, fermentation efficiency, physical stability of the beads, pH, residual sugar, and total microbial count. The results of the study showed that the alginate matrix without PVA produced the highest ethanol yield of 34.8 mL, with an efficiency of 83.8%, and remained stable through the eighth cycle. Meanwhile, the addition of 0.5%, 1%, 1.5%, and 2% PVA, respectively, yielded a maximum ethanol yield of 34.0 mL with an efficiency of 81.8%, lasting until the seventh cycle; a maximum ethanol yield of 33.5 mL with an efficiency of 62.6%, lasting until the sixth cycle; a maximum ethanol yield of 33.0 mL, an efficiency of 61.7%, lasting until the sixth cycle; and a maximum ethanol yield of 32.0 mL, an efficiency of 56.7%, lasting until the fifth cycle. With the addition of PVA, the durability of the alginate-IS258 matrix did not improve over the fermentation cycles. These results indicate that the alginate matrix without PVA addition exhibits the best durability because it can be used for a longer period during the fermentation cycles.