Enzymatic Cross-Linking of Alkali Extracted Arabinoxylans: Gel Rheological and Structural Characteristics

Ferulated arabinoxylans were alkali-extracted from wheat bran at different incubation times (0.0, 0.5, 1.0, 1.5 and 2.0 h). Wheat bran ferulated arabinoxylans (WBAX) arabinose-to-xylose ratio, ferulic acid content, intrinsic viscosity and viscosimetric molecular weight values decreased as the incubation time of extraction increased. WBAX enzymatic cross-linking capability was affected by incubation time while an increase in WBAX concentration from 5 to 6% (w/v) favored gelation. The WBAX gels formed presented a macroporous structure with mesh size ranging from 40 to 119 nm and hardness values varying from 1.7 to 5 N

Anaerobic cometabolism of fruit and vegetable wastes using mammalian fecal inoculums: Fast assessment of biomethane production

Anaerobic digestion (AD) is a biological process which produces biomethane as energy source, using waste as substrate. Cometabolism is a novel way to enhance liquid AD, via augmenting the biodiversity of inoculums, especially in the hitherto little-studied 96-h initiation period critical to AD startup. Dog, horse and sheep feces were used as sources of inoculum and mixed with fruit and vegetable waste (FVW) and water. Thermophilic (55 C), mesophilic (39 ) and psychrophilic (25 C) AD conditions were tested. As inoculum and water quantities alter the abundance and diversity of the anaerobic communities, 1:1 and 1:4 ratios of FVW feedstock to inoculum solutions were compared. Live Saccharomyces cerevisiae was supplemented as probiotic in the anaerobic reactors. Biogas, CO2 and CH4 were measured as well as digestion of FVW. Results showed consistently more CH4 production under cometabolism, higher inoculum density and thermophilic conditions; higher CH4, pH and digestion simultaneously occurred in the mixed-inoculum reactors. A strong relationship between biogas and its CO2 and CH4 main components was found. Horse inoculum in the mixed reactors enhanced CH4 production; sheep inoculums improved digestibility; and the dog inoculum seemed to neutralize pH. S. cerevisiae may have improved cellulolytic activity in FVW digestion at 25 and 39 C, and provided an energy and nutrient source at 55 C

Physicochemical variability and nutritional and functional characteristics of xoconostles (

Introduction. The genus Opuntia generally produces fruits with abundant pulp and sweet taste, but also acidic fruits known as xoconostles, which may have a high potential for use and consumption. The aim of this study was to evaluate the physicochemical, nutritional and functional characteristics of 10 xoconostle genotypes produced in Mexico. Materials and methods. The xoconostle genotypes were collected from Hidalgo, Zacatecas and State of Mexico in Mexico. The pH, soluble solids, and titratable acidity, as well as the proximate composition and content of total phenolic compounds, betalains and antioxidant capacity (Trolox) were determined. Results were analyzed using analysis of variance (ANOVA) procedures and the Tukey test at a significance level of 0.05. Results and discussion. It was observed a high variability in weight (44.5–84.3 g FW), soluble solids (4.2–6.12 °Brix), titratable acidity (0.10–0.19 g 100 g-1 FW), and pH (2.74–3.54) among the 10 genotypes of Opuntia spp. studied. The protein content varied from 0.60 to 0.87 g 100 g-1 FW. Xoconostle genotypes with high calcium content of 1.008 mg 100 g-1 FW were identified. Some xoconostle genotypes can be a good source of pigments due to their high content of betacyanins (0.76–5.06 mg 100 g-1 FW) and vulgaxanthins (1.83–4.76 mg 100 g-1 FW). The antioxidant capacity of some xoconostle genotypes was higher than that of other common fruits. Conclusion. The xoconostle genotypes evaluated have a potential to be exploited as a suitable source of pigments and antioxidant compounds

Soil bacterial consortia and previous exposure enhance the biodegradation of sulfonamides from pig manure

Persistence or degradation of synthetic antibiotics in soil is crucial in assessing their environmental risks. Microbial catabolic activity in a sandy loamy soil with pig manure using C-12- and C-14-labelled sulfamethazine (SMZ) respirometry showed that SMZ was not readily degradable. But after 100 days, degradation in sulfadiazine-exposed manure was 9.2%, far greater than soil and organic manure (0.5% and 0.11%, respectively, p < 0.05). Abiotic degradation was not detected suggesting microbial catabolism as main degradation mechanism. Terminal restriction fragment length polymorphism showed biodiversity increases within 1 day of SMZ spiking and especially after 200 days, although some species plummeted. A clone library from the treatment with highest degradation showed that most bacteria belonged to alpha, beta and gamma classes of Proteobacteria, Firmicutes, Bacteroidetes and Acidobacteria. Proteobacteria (alpha, beta and gamma), Firmicutes and Bacteroidetes which were the most abundant classes on day 1 also decreased most following prolonged exposure. From the matrix showing the highest degradation rate, 17 SMZ-resistant isolates biodegraded low levels of (14) C-labelled SMZ when each species was incubated separately (0.2-1.5%) but biodegradation was enhanced when the four isolates with the highest biodegradation were incubated in a consortium (Bacillus licheniformis, Pseudomonas putida, Alcaligenes sp. and Aquamicrobium defluvium as per 16S rRNA gene sequencing), removing up to 7.8% of SMZ after 20 days. One of these species (B. licheniformis) was a known livestock and occasional human pathogen. Despite an environmental role of these species in sulfonamide bioremediation, the possibility of horizontal transfer of pathogenicity and resistance genes should caution against an indiscriminate use of these species as sulfonamide degraders