Sugarcane juice was converted to ethanol by Saccharomyces cerevisiae producing 8% (v/v) ethanol. This ethanol was used for vinegar production using adsorbed (bagasse, corn cobs and wood shavings) and entrapped (calcium alginate) cells of Acetobacter aceti NRRL 746. All three adsorbed carrier materials were statistically similar for acetic acid production and produced acidity from 5.9 to 6.7% after 28 days of submerged fermentation. By recycling bagasse adsorbed cells, the time of acetic acid fermentation was reduced to 13 days. Semi-continuous fermentation of bagasse adsorbed cells using a packed bed column further reduced the fermentation time to 80 h.

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The fermented tea vinegar combines the beneficial properties of tea and vinegar. The complete fermentation takes 4 to 5 weeks in a batch culture and thus can be shortened by semi continuous/ continuous fermentation using immobilized bacterial cells. In the present study, alcoholic fermentation of 1.0 and 1.5% tea infusions using Saccharomyces cerevisae G was carried out that resulted in 84.3 and 84.8% fermentation efficiency (FE) respectively. The batch vinegar fermentation of these wines with Acetobacter aceti NRRL 746 at the initial 1% acidity yielded 4.5 and 4.7% volatile acidity with 71.4 and 73% FE in 24 days. The semi continuous fermentation using sugarcane bagasse adsorbeded A.aceti cells produced 4.4% of volatile acidity from 1.5% tea wine (8.9% ethanol and 1.0% acidity), in 9 flow cycles, each of 4 h duration in a fermentation column at 50 ml/h. In the scale up process, 600 ml 1.5% tea wine produced 4.3% volatile acidity at 42.7% FE in 9 flow cycles of 12 h duration each.

Three consortia were developed out of the ligninolytic fungal isolates for pretreatment of rice straw. The fungal consortium of Pleurotus ostreatus and Phanerochaete chrysosporium, produced maximum laccase (Lac), lignin peroxidase (LiP), and manganese peroxidase (MnP) activities of 2.40 nkat/gds, 37.92 nkat/gds, and 62.50 nkat/gds, respectively. Response surface methodology (RSM) based on central composite design (CCD) was used to optimize pretreatment of rice straw under solid state conditions. With a desirability value of 0.862, the optimum conditions (moisture, 121.1%; temperature, 31.3°C; and log spore count, 8.0 spores/mL) resulted in 43.0%, 12.7% and 7.0% cellulose, hemicellulose, and lignin, respectively, from an initial respective values of 39.5%, 23.3%, and 11.5%. Optimization under shake flask conditions using 2.5 g rice straw, 8.0 mL concentrated ligninolytic enzyme extract, 10 mM Ca2+ ions, 45°C incubation temperature in an incubation period of 72 h resulted in 56.4%, 12.2%, and 2.2%, cellulose, hemicellulose, and lignin, respectively. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 635–646, 2019

Thermophilic Aspergillus terreus RWY produced cellulases and xylanases in optimal concentrations at 45 °C in solid state fermentation process, though enzyme production was also observed at 50 and 55 °C. Filter paper cellulase (FP), endoglucanase (EG), β-glucosidase (BGL), cellobiohydrolase (CBH), xylanase, β-xylosidase, α-L-arabinofuranosidase and xylan esterase activities for A. terreus RWY at 45 °C in 72 h were 11.3 ± 0.65, 103 ± 6.4, 122.5 ± 8.7, 10.3 ± 0.66, 872 ± 22.5, 22.1 ± 0.75, 126.4 ± 8.4 and 907 ± 15.5 U (g-ds)(-1) , respectively. Enzyme was optimally active at temperatures and pH ranging between 50-60 °C and 4.0-6.0, respectively. The half life (T1/2 ) of 270 and 240 min at 70 and 75 °C, respectively for the enzyme indicates its stability at higher temperatures. The addition of MnCl2 , CoCl2 , and FeCl3 significantly enhanced cellulase activity. Enzyme demonstrated multiplicity by having seven, one and three isoform(s) for EG, CBH and BGL, respectively. Significant production of functionally active consortium of cellulolytic and xylanolytic enzymes from A. terreus RWY makes it a potential candidate in bioprocessing applications.

Sugarcane with a high content of sugar is a potential substrate for making vinegar through alcoholic and acetous fermentation. As an alternative to the longer traditional batch scale vinegar fermentation, a fermentation process involving successive discontinuous cycles of acetification was developed. The cycles standardized for 3 days of shaking (75 rpm) and addition of (NH4) 2SO4 and KH2PO4 were recycled with previous lots of fermentation resulting in vinegar production with a time period of 7.6 days compared with 24 days of batch fermentation. The volatile's characterization of sugarcane vinegar identified 50 compounds with 24 esters, 4 alcohols, 2 phenols (aromatic hydrocarbons), 3 ketones, 6 alkene derivative, 3 carboxylic acids, 1 aldehyde and 8 miscellaneous compounds. Physicochemical characterization of vinegar revealed a maximum total phenol content of 67.09 Ϯ 1.21 mg/100 mL in control while ascorbic acid content of 108.49 Ϯ 1.11 mg/100 mL was best obtained in the treatment of shaking at 75 rpm along with supplements. PRACTICAL APPLICATIONSThe result of this work will have practical applications in providing a less timeconsuming and highly efficient method for vinegar production thus, promoting an impetus to the setting up of natural vinegar production plants in this part of the country.

The present study was conducted to optimize fermentation parameters for apple wine production using Golden Delicious apples. Physicochemical analysis of the cultivar revealed a°Brix-acid ratio of 24.61 with ample amount of total and reducing sugars (9.6 and 6.03% w/v); making it a suitable substrate to produce ethanol. Microbiological analysis lead to isolation of a yeast strain (namely A2) which was molecularly identified and accessed at GenBank as S. cerevisiae KY069279. Ethanol fermentation optimization using response surface methodology revealed that a temperature of 20°C, an inoculum size of 7.08 (%v/v) and diammonium hydrogen phosphate supplementation @ 154.4 mg/100 mL as optimum for apple wine production which lead to 10.73% (v/v) ethanol production with a desirability of 86.9%. Fresh wine having malic acid content of 1.87 (mg/100 mL) was subjected to malolactic fermentation (MLF) for 8 days using Leuconostoc oenos NCIM 2219 resulting in apple wine having 0.4 (mg/100 mL) malic acid. Sensory analysis of MLF and non-MLF apple wines categorised them as superior quality with average scores of 69.5 and 74.5, respectively. Gas chromatography-mass spectrometric analysis of apple wine revealed the presence of 38 volatile compounds including higher alcohols, acids, esters etc. The study thus revealed a process for apple wine preparation using an indigenous yeast and also optimized and compared malolactic and non-malolactic fermented ciders.

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