Bioactive, structural, and mechanical properties were measured of a cellulose biopolymer produced by Gluconacetobacter xylinus using hydrolyzed collagen and phenolic compounds from teas and grape pomace (GP) in an optimized culture medium. Biopolymers were impregnated with an antibiotic to investigate possible antibacterial activities. Hybrid bacterial cellulose (BC)-collagen membranes obtained from cultures with green tea and a ternary mixture (TM) of teas with GP presented a high concentration of phenolic compounds (879.7 and 1312.8 mg gallic acid equivalent per liter) and antioxidant activity (973.3 and 575.9 mmol/g), respectively. BC membranes included a nanodimensional network of microfibrils, and the addition of hydrolyzed collagen in the TM of teas in situ resulted in thicker structures with improved mechanical properties. BC-collagen membranes pretreated with cephalexin exhibited significant inhibition against Escherichia coli and Staphylococcus aureus. The enrichment of the culture media with plant phenolic compounds and collagen resulted in the formation of hybrid BC membranes in a shorter time when compared to those produced without these components. Membranes modified with bioactive compounds in situ and antibiotics ex situ can be turned into potential products for application in biomaterials with antioxidant activity.

The residual Saccharomyces cerevisiae from brewing was used as a biosorbent of flavonoids of hydro alcoholic extract from samples of grape pomace (Merlot and Tannat). Biosorption assays verified that the pseudo-second order kinetic model and the Dubinin-Raduschkevich isotherm model presented the best fit, with free energy of adsorption (E) of 7.1 and 6.5 kJ for the Merlot and Tannat varieties, respectively, indicating that the yeast has many binding sites and adsorption was a physical process. The analysis of microscopy and spectroscopy showed differences in structure and composition of the yeast after biosorption, demonstrating that the application was effective, which was confirmed by the chromatographic analysis, where a reduction in 17% and 50% in the catechin peak was observed in the Merlot and Tannat samples, respectively. Finally, there was an increase in the in vitro bioaccessibility of flavonoids in 68% for the Merlot sample and 88% for Tannat, reaching the main objective of this application. Determination of biosorption kineticsAs described by Stafussa et al. (2016), to perform biosorption kinetics, 125 mL Erlenmeyer flasks containing 50 mg of yeast S. cerevisiae (dry weight), and 12.5 mL of solution of grape pomace hydroalcoholic extract were used. The flasks were shaken at 130 r.p.m. and 25°C, and samples were taken at