Abstract To optimize the process technology of yogurt fortified with M. esculenta, first, the Plackett-Burman experimental design combined with the central composite design (CCD) were used to investigate the effects of four parameters on the sensory score. Then, artificial neural networks (ANN) and genetic algorithm (GA) were used to evaluate the process parameters of the fortified yogurt. Finally, the quality of the yogurt prepared under optimal conditions were observed. The results showed that the optimal parameters from ANN-GA were: 0.2 g of mycelia, 15 g milk powder, 6.4 g sucrose, and a fermentation temperature of 38 °C, with the highest predicted sensory score of 97.1 points, which was more accurate and reliable than CCD. Mycelia of M. esculenta gave the yogurt excellent quality, including good acidity (95 ± 2.85° T) and water holding capacity (64.32 ± 4.25%) after 21 days storage at 4 °C; firmness (12.98 ± 1.25) g, consistency (22.85 ± 0.92) g·sec, stickness (-6.16 ± 0.38) g, stringiness (3.53 ± 0.12) mm, and cohesion index (-6.62 ± 1.75) g·sec. Moreover, the living lactic acid bacteria of the yogurt with M. esculenta (6.23 ± 0.23) × 107 CFU/mL) were significantly higher than that of the control yogurt (5.65 ± 0.31) × 107 CFU/mL. This could provide a theoretical basis and parameter guidance for developing a new functional yogurt.

ABSTRACT In this study, a high salt-tolerant and glyphosate-degrading strain named BZ8 was isolated from activated sludge. According to 16S rDNA sequencing methods, morphological, physiological and biochemical analysis, strain BZ8 was identified as Agrobacterium tumefaciens. The growth and glyphosate-degrading capability of A. tumefaciens BZ8 were investigated and the results showed that the optimum conditions for glyphosate degradation under 6% of NaCl concentration were found as follows: inoculation size of 10% (v/v), incubation temperature 37℃ and initial pH of 5.0. Salt tolerance test showed that A. tumefaciens BZ8 grew well and could thoroughly degrade 2000 mg/L glyphosate in 36 h if the concentration of NaCl was lower than 6%, while the degradation rate decreased gradually with increasing NaCl concentration. But the glyphosate degradation rate could still reach 62% when the salt concentration was 8%. In addition, the kinetic parameters for A. tumefaciens BZ8 grown on 100-2800 mg/L glyphosate according to Haldane’s model could predict the cell growth tendency successfully. These results showed that A. tumefaciens BZ8 could be used to control glyphosate wastewater with high salt content. Therefore, it has potential application.

The enzymatic hydrolysis of food waste by commercially available enzymes and the subsequent ethanol fermentation of the hydrolysates by Saccharomyces cerecisiae H058 were studied in this work. The optimum batch enzymatic conditions were found to be saccharification pH of 4.5, temperature of 55!, glucoamylase concentration of 120 u/g, α-amylase concentration of 10 u/g, solid-liquid ratio of 1: 0.75 (w/w). Fed batch hydrolysis process was started with a solid-liquid ratio of 1: 1 (w/w), with solid food waste added at time lapse of 2 h to get a final solid-liquid ratio of 1: 0.5 (w/w). After 4 h of reaction, the reducing sugar concentration reached 194.43 g/L with a enzymatic digestibility of 93.12%. Further fermentation of the batch and fed batch enzymatic hydrolysates, which contained reducing sugar concentration of 131.41 and 194.43 g/L respectively, was performed using Saccharomyces cerevisiae H058, 62.93 and 90.72 g/L ethanol was obtained within 48 h.