Fermentative Production of Sugarcane Vinegar by Immobilized Cells of Acetobacter aceti Under Packed Bed conditions

Abstract

Sugarcane juice (17 °Bx), the substrate of choice for vinegar production due to its high sugar content and easy availability was fermented to ethanol by Saccharomyces cerevisiae strain 35 producing 9.5 % (v/v) ethanol. This ethanol was used for vinegar production using immobilized cells of Acetobacter aceti AC1 (on wood shavings with cell to adsorbent ratio of 2:1) packed in an indigenously developed polyvinyl chloride column. Sugarcane ethanol (supplemented with mother vinegar) with an initial acidity of 2 % (w/v) was trickled at 50 ml/h through the packed bed at 2.5 l scale, that produced sugarcane vinegar in 72 h (compared to 13 days of batch cycle). The vinegar production was consistent over 25 cycles studied and had a volatile acidity of 4.08–6.84 % (w/v), fermentation efficiency (52.9–87.9 %), acetification rate (5.8–22.8 g/l/day) and yield factor (0.68–1.14). The sugarcane vinegar had a good sensory score (8.66 ± 0.33), improved total phenols (81.9 ± 0.14–138.6 ± 0.49 mg/100 ml) with retention of ascorbic acid (42.0 ± 1.13–86.5 ± 1.34 mg/100 ml).