The Effect on Ethanol Production Using Red Seaweed Extracts in Sugarcane Juice Treatment

The present study assessed the clarification of sugarcane juice using different flocculants and their effect on ethanol yield. The extracted sugarcane samples (CTC072361—harvest 2022/2023) were adjusted to 16% Brix, and calcium hydroxide (56 g L⁻¹) was added with pH 7.0 ± 0.4 and boiled. The clarification test was done, using the anionic synthetic polymer, commercial organic flocculant and red seaweed extract (RSE—Kappaphycus alvarezii) for sedimentation of impurities. After a retention time of 20 min, the clarified broths were collected by siphoning and analyzed for Brix, total reducing sugars (TRS), pH, total acidity, and total phenolic compounds. The extracted sugarcane juice was analyzed for Brix, TRS, reducing sugars, Pol, pH, purity, acidity, ash, total phenolic compounds, turbidity, and starch content. The clarified juices were standardized to obtain the wort and analyzed for TRS and total acidity. The worts were processed for fermentation process, using CAT-1 yeast (30 g L⁻¹). After fermentation (Brix ≤ 1%), the wine samples were collected and analyzed for total residual reducing sugars, pH, total acids, alcohol content and glycerol, with subsequent calculation of fermentation efficiency. The use of red algae extracts (Kappaphycus alvarezii) was found efficient as a bioflocculant for removing impurities in sugarcane juice and promoted a similar clarification process with synthetic and organic flocculants. The use of red seaweed resulted in as fermentation efficiency 93.27% and represented up to 3.4% higher than the other treatments.