Novel routes for valorisation of grape pomace through the production of bioactives by Aspergillus niger

Abstract: Grape pomace is an abundant winery by-product produced worldwide, which contains a high concentration of polyphenols trapped in cell wall fibers. The fungus tannase enzyme finds many applications in the industry, but its use is currently limited. This is due to its high production cost derived from tannic acid, which is the typical inductor of tannase enzyme by Aspergillus species. Therefore, assessment of natural tannin sources as inductors is a strategy to overcome this limitation. We propose here to employ the red grape pomace, which is a rich source of tannins and polyphenols. We found that, although grape pomace is not able to induce tannase by itself, it is a useful complement for tannic acid induction, reducing the concentration of tannic acid necessary to achieve maximum levels of tannase induction, which ranged between 3.0 and 4.5 U/mL. We also explored the potential usage of this biomass to induce other relevant industrial enzymes and quantified the recovery of gallic acid from grape pomace by the fungus fermentation; finding new routes for this by-product valorisation.Fil: Meini, María Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Biológica. Área Biofísica; ArgentinaFil: Ricardi, Laura Lis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; ArgentinaFil: Romanini, Diana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Tecnología; Argentin

Engineering a short-chain dehydrogenase/reductase for the stereoselective production of (2S,3R,4S)-4-hydroxyisoleucine with three asymmetric centers

Abstract Fenugreek is a dietary supplement for anti-aging and human health. (2S,3R,4S)-4-hydroxyisoleucine (4-HIL), which is extracted from fenugreek seeds, is expected to be a promising orally active drug for diabetes and diabetic nephropathy because of its insulinotropic effect. Although several chemical synthesis methods of 4-HIL have been proposed, these methods require multistep reactions to control the stereochemistry of 4-HIL. In this study, we modified the key enzyme 4-HIL dehydrogenase (HILDH) to overcome the biggest limitation in commercial-scale production of 4-HIL. As a result, an effective one-step carbonyl reduction to produce (2S,3R,4S)-4-HIL was successfully accomplished with strict stereoselectivity (>99% de). Mass production of (2S,3R,4S)-4-HIL by our synthetic method could have a significant contribution to the prevention of diabetes, dyslipidemia, and Alzheimer’s disease. (120 words/200 words