Microbial cellulases are highly versatile catalysts with significant potential in various industries, including pulp and paper, textile manufacturing, laundry, biofuel production, food and animal feed, brewing, and agriculture. Cellulases have attracted considerable attention from the scientific community owing to their broad industrial applications and the complex nature of enzymatic systems. In the present study, a novel fungal isolate of Aspergillus sp. IN5 was used to produce cellulases. We optimized each parameter, including carbon source, incubation temperature, pH, and incubation time, for maximum cellulase production using isolate IN5 under solid-state fermentation conditions. The optimized parameters for cellulase production by isolate IN5 under solid-state fermentation were as follows: substrate, soybean residue; incubation temperature, 35 °C; pH, 7.0; and incubation duration, 5 days. These conditions resulted in the highest total cellulase activity (0.26 U/g substrate), and carboxymethyl cellulase and β-glucosidase activities of 3.32 and 196.09 U/g substrate, respectively. The obtained fungal cellulase was used for the enzymatic hydrolysis of acid- or alkali-pretreated rice straw, which served as a model substrate. Notably, compared with acid pretreatment, the pretreatment of rice straw with diluted alkali led to higher yields of reducing sugars. Maximum reducing sugar yield (286.06 ± 2.77 mg/g substrate) was obtained after 24-h incubation of diluted alkali-pretreated rice straw mixed with an enzyme loading of 15 U/g substrate. The findings of this study provide an alternative strategy for utilizing agricultural waste and an approach to efficiently produce cellulase for the degradation of lignocellulosic materials, with promising benefits for sustainable waste management.

Textile waste usually ends up in landfills and causes environmental pollution. In this study, pretreatment methods for textile recycling, including autoclaving, freezing alkali/urea soaking, and alkaline pretreatment, were applied to textile waste with various cotton/polyester blending ratios. The best condition for enzymatic hydrolysis was a 60/40 textile waste blend of cotton/polyethylene terephthalate (PET) with a reusable chemical pretreatment (15% NaOH) at 121 °C for 15 min. The hydrolysis of pretreated textile waste by cellulase was optimized using response surface methodology (RSM) based on central composite design (CCD). The optimized conditions were 30 FPU/g of enzyme loading and 7% of substrate loading, which resulted in a maximum observed value of hydrolysis yield at 89.7%, corresponding to the predicted value of 87.8% after 96 h of incubation. The findings of this study suggest an optimistic solution for textile waste recycling.

This research investigated the impact of the concentration of pineapple juice on the characteristics of pineapple wine during fermentation with Saccharomyces cerevisiae var. burgundy. Three ratios of fresh pineapple juice to water were mixed to obtain three treatments, which were T1—2:1, T2—1:1, and T3—1:2. The °Brix and pH of all pineapple juice and water ratios were adjusted to 25 and 4, respectively. The results showed that changes in alcohol, pH, Total Soluble Solids (TSS), Total Titratable Acidity (TAA, as citric acid), and Volatile Acidity (VA, as acetic acid) during the 10-day fermentation among three treatments were significantly different. The highest alcohol content was obtained from the 2:1 with values of 10.71% (v/v). The mixed ratio at 1:1 and 1:2 obtained the alcohol value of 9.61 and 8.35% (v/v), respectively. After ten days of fermentation, TSS, pH values, TAA, and VA were in the range of 9.7–13 °Brix, 3.56–3.82, 0.384–0.448, and 0.0013–0.0016, respectively. However, the appearance, aroma, and taste of all ratios were not significantly different. Sweetness and overall liking, wine with pineapple juice/water ratio at 2:1 had the highest score (p ≤ 0.05). The total antioxidant activities determined by DPPH and total phenolic content were 0.91 mmol/L TE and 365.80 mg/L GAE, respectively, as confirmed by FTIR spectral analyses.

Plum has long been cultivated in northern Thailand and evolved into products having long shelf lives. In this study, plum processing was analyzed by comparing the production of plum wine using three types of yeast, Saccharomyces cerevisiae var. burgundy, Hanseniaspora thailandica Zal1, and S. cerevisiae Lalvin EC1118. EC1118 exhibited the highest alcohol content (9.31%), similar to that of burgundy (9.21%), and H. thailandica Zal1 had the lowest alcohol content (8.07%) after 14 days of fermentation. Plum wine fermented by S. cerevisiae var. burgundy had the highest total phenolic (TP) content and antioxidant activity of 469.84 ± 6.95 mg GAE/L and 304.36 ± 6.24 µg TE/g, respectively, similar to that fermented by EC1118 (418.27 ± 3.40 mg GAE/L 288.2 ± 7.9 µg TE/g). H. thailandica Zal1 exhibited the least amount of TP content and antioxidant activity; however, the volatility produced by H. thailandica Zal1 resulted in a plum wine with a distinct aroma.

Pineapples are a tropical fruit with high nutritional value and high vitamin and sugar contents. In this study, low-grade pineapples were fermented to produce vinegar using surface culture fermentation (SCF), which involved the addition of dragon fruit juice, to compare the quality and antioxidant activity of different preparations of vinegar. The highest acetic acid concentration (7.35%) was obtained from pineapple vinegar after 20 days of incubation. Vinegar made from mixed pineapple and dragon fruit juice without peel and vinegar with pineapple and dragon fruit juice with peel had acetic acid concentrations of up to 6.20% and 4.50%, respectively. The mixed-fruit vinegar of pineapple and dragon fruit juice with peel displayed the highest antioxidant activity at 210.74 µg/g TE, while no significant difference was found between the other two vinegars (189.52 vs. 187.91 µg/L TE). Notably, the volatile compounds detected in the vinegars were alcohols and esters, which may contribute to the distinct aroma. Overall, the addition of dragon fruit juice with peel to pineapple vinegar increased the phenolic content and antioxidant activity; however, fermentation was slightly slower than that of the other two test materials.

Dragon fruit has many potential health benefits. It is inexpensive and widely cultivated in Thailand. The addition of dragon fruit to pineapple vinegar may help enhance the total phenolic compounds and antioxidant activity. This study aimed to study and compare the chemical characteristics of vinegar produced via one-step fermentation of a mixture of pineapple and dragon fruit juice from Krok Phra District of Thailand using Saccharomyces cerevisiae var. burgundy with that obtained using sequential fermentation using Saccharomyces cerevisiae var. burgundy and Acetobacter aceti. When the two fermentation methods were compared on day 20, the maximum acetic acid concentration obtained from sequential fermentation was 5.79 ± 0.25%, which was higher than that obtained in one-step fermentation (1.93%). The total phenolic compound content in the mixed fruit vinegar obtained from sequential fermentation and one-step fermentation was 228.01 and 242.2 mg/L gallic acid equivalents, respectively. The antioxidant content of the products obtained in sequential and one-step fermentations was 187.91 mg/L GAE and 209.33 µg/g of Trolox equivalents, respectively, which was consistent with the total phenolic compound content. This indicated that the acetic acid content in the mixed pineapple and dragon fruit juice vinegar obtained using sequential fermentation was higher than that obtained using one-step fermentation although its total phenolic content and the antioxidant activities were slightly lower. These observations will be useful for improving vinegar fermentation in the area.