Optimization of biosynthesis conditions and catalitic behavior evaluation of cellulase-free xylanase produced by a new Streptomyces sp. strain

Cellulase-free xylanase by Streptomyces sp.P12-137 was obtained bycultivation on the wheat bran as the sole carbon source. The effect of carbon and nitrogen sources and a ratio of them on the cellulase-free xylanase production was investigated. The new isolate Streptomyces sp. strain was able to grow in submerged system and to produce an increased level of xylanase. Wheat bran induced xylanase biosynthesis yield at a high level (9.27 UA/ml). For economical reasons cultivation was achieved on a cheap fermentative medium represented by agro-industrial wastes. The optima of the pH and temperature of the crude xylanase activity were 5.5 and 70°C,respectively

Extraction Optimization and Valorization of the Cornelian Cherry Fruits Extracts: Evidence on Antioxidant Activity and Food Applications

In this work, the optimization of two extraction methods, conventional CE and ultrasound-assisted UAE, to obtain extracts from cornelian cherry fruit with high antioxidant activity, which can be used to produce healthier jelly candies, is presented. In the CE process, the effects of temperature (30–50 °C), time (15–45 min), and hydroalcoholic mixtures (60–100% ethanol, v/v) were studied. The highest antioxidant activity (29.83 ± 0.85 mg TE/g dw) was found in the extracts obtained using 60% ethanol at 40 °C for 15 min. The UAE process led to comparable values of 26.60 ± 0.53 mg TE/g dw at 40% amplitude and pulsed sonication (5 s on and 5 s off) for 12.5 min. Under these experimental conditions, the specific energy consumed was 1.91 kJ/g. The vitamin C content and its inhibitory activity against metabolic enzymes were evaluated in extracts with different antioxidant activity. A significant inhibitory effect against carbohydrate-metabolism-associated enzymes was identified for all the tested extracts, with an inhibitory effect against α-glucosidase higher than 75%, but with a lower effect against α-amylase. The extract obtained by CE (60% ethanol, 40 °C, 15 min) provided the highest vitamin C content of 39.9 ± 1.2 mg ascorbic acid/100 g dw. Four variants of the healthier jelly candies were formulated, with a vitamin C content of 0.34 mg ascorbic acid/100 g dw in samples with agar-agar and 0.70 mg ascorbic acid/100 g dw in samples with gelatin.Romanian Ministry of Research and Innovation, CNCS-UEFISCDI, project numbers PN-III-P1-1.1-MC-2019-1905 and PN-III-P1-1.1-MC-2019-1908, within PNCDI III. The APC was funded by M.T.S. The authors are also grateful to Junta de Castilla y León (Spain) and ERDF for the financial support of project BU050P20. The Ó. Benito–Román post-doctoral contract was funded by Junta de Castilla y León (Spain) and ERDF through project BU050P20 and by Agencia Estatal de Investigación through project PID2020-116716RJ-I00/AEI/10.13039/501100011033

Optimization of xylanase production by Streptomyces sp. P12-137 using response surface methodology and central composite design

Response surface methodology and central composite design were used to optimize a biosynthesis medium for the production of xylanases by Streptomyces sp. P12-137 in submerged fermentation culture at pH 5.0, with wheat bran as substrate. The three variables involved in this research were the wheat bran, potassium nitrate and xylose concentrations. Statistical analysis of the results showed that, in the range studied, xylose and potassium nitrate concentrations had a significant effect on xylanase production. The optimized biosynthesis medium contained (in %, w/v): wheat bran 1.0, KNO3 1.0, xylose 0.5. This medium resulted in a 3-fold increased level of the xylanase (27.77 UA/ml) production compared to the initial level (8.30 UA/ml) after 120 h of fermentation, whereas the value predicted by the quadratic model was 26.45 UA/ml

Modeling process for bioproduction of xylanase by Streptomyces spp. p12-137 on lignocelluloses agro-wastes

The production of xylanase without cellulase is required for the prebleaching of pulps, paper and food industry. The strain Streptomyces spp.P12-137 developed from the spores of the wild type organism was used in this work. Cultures in Erlenmeyer flasks, under shaking condition (150 rpm) at temperature and pH values (28°C, 5.0 respectively) revealed a xylanase activity of 27.77 IU·mL-1 after 120 h fermentation. This study demonstrates that Streptomyces spp. P12-137 is able to produce xylanase when wheat bran is used as a substrate. Fermentation was performed in a glass bioreactor withforced aeration. Data obtained have been compared to data from mathematical model obtained by numerical simulation using Matlab 7.9.0.529 (MathWorks, Inc. USA). The numerical simulation of the bioprocess could be a useful tool for adopting a control strategy to achieve increased xylanases yields under pilot or industrial conditions

Optimization of protein production by Geotrichum candidum MIUG 2.15 by cultivation on paper residues, using response surface methodology

Response surface methodology (RSM) based on the 23 factorial central composite design (CCD) was used to optimize the biotechnological conditions for growth and protein production by a selected fungal strain Geotrichum candidum MIUG 2.15, by solid-state cultivation on a semisolid medium based on a mixture of paper residues, i.e. office paper, newspaper, and cardboard, mixed in a ratio of 1:1:1(w/w), supplemented with cheese whey waste and complex manure. Three independent variables, the solid:liquid ratio, the concentration of complex manure, and cultivation time, were evaluated to determine their correlative effect on biomass production and protein biosynthesis. The optimal conditions for obtaining a maximum protein yield of 9.53% w/w dry mass were the following: the complex manure concentration of 0.5%, the solid:liquid ratio of 1:5, and the growth time of 10 days

Bioethanol production by solid state fermentation from cheese whey mixed with brewer’s spent grains

Food by-products, whey mixed with spent grains are renewable resources which can be used as fermentation susbtrates for bioethanol production using selected Kluyveromyces spp. yeast strains. These food by-products have extensive results as wastes in food industry, are cheap and readily available sources and their use has also important benefit for the environmental protection. The ability of some Kluyveromyces spp. yeast strains (commercial starter culture and wild culture) to ferment the carbohydrates mixture from a complex fermentation substrate based on hydrolyzed brewer’s spent grains and cheese whey was analyzed. Three brewer’s spent grains (hydrolyzed) and cheese whey (heat treated) ratios (1:1, 1:2 and 2:1) were considered in the study. Studies have shown that using an optimum combination of fermentation substrate, respectively hydrolyzed brewer’s spent grains and heat treated cheese whey in ratio of 1:2 have influence on yeast fermentation behavior and yield ethanol production