Lilia A. Prado-Barragan

Microbial tannases: advances and perspectives

In the last years, tannase has been the subject of a lot of studies due to its commercial importance and complexity as catalytic molecule. Tannases are capable of hydrolyzing complex tannins, which represent the main chemical group of natural anti-microbials occurring in the plants. The general outline of this work includes information of the substrates, the enzyme, and the applications. This review considers in its introduction the concepts and history of tannase and explores scientific and technological aspects. The “advances” trace the route from the general, molecular, catalytic, and functional information obtained under close to optimal conditions for microbial production through purification, description of the enzyme properties, and the commercial applications to the “perspectives” including expression studies, regulation, and potential uses; aspects related to the progress in our understanding of tannin biodegradation are also included.

Microbial production of ellagic acid and biodegradation of ellagitannins

In the last years, tannin biodegradation has been the subject of a lot of studies due to its commercial importance and scientific relevance. Tannins are molecules of low biodegradation and represent the main chemical group of natural anti-microbials occurring in the plants. Among the different kinds of tannins, ellagitannins represent the group less studied manly due to their diversity and chemical complexity. The general outline of this work includes information on tannins, their classification and properties, biodegradation, ellagic acid production, and potential applications. In addition, it describes molecular, catalytic, and functional information. Special attention has been focused on the biodegradation of ellagitannins describing the possible role of microbial enzymes in the production of ellagic acid.

Extraction and analysis of ellagic acid from novel complex sources

Ellagic acid (EA) was quantified by reversed-phase high-performance liquid chromatography (RPHPLC) coupled with photodiode array detection (DAD) in five fine-powdered plants collected from the semiarid region of Mexico. Samples analysed included Jatropha dioica branches (Dragon’s blood), Euphorbia antisyphyllitica branches (Candelilla), Turnera diffusa Willd leaves (Damiana), Flourensia cernua leaves (hojasén) and Punica granatum husk (pomegranate) at two maturity stages (“turning” or intermediate and maturated fruit, considered as positive controls). The results demonstrated high EA concentrations in all tested samples which are novel sources of this natural antioxidant. The method developed for the EA analysis is fast and it showed an excellent linearity range, repeatability, intra-and inter-day precision and accuracy with respect to the methods reported for the EA analysis.

Microbial and enzymatic hydrolysis of tannic acid: influence of substrate chemical quality

Tannic acid is commonly employed as the main component in culture media for the selection of tannase-producing strains. In biotechnological processes it is the favorite substrate used to induce the tannase enzyme in both solid and submerged culture for microbial and/or enzymatic production of gallic acid. However, the results found in literature are inconsistent notwithstanding the strict control of all parameters that rule the bioprocesses. The present work, for the first time, reveals the importance of differences in the quality and chemical profile of tannic acid from different suppliers and their influence on the fungal and enzymatic hydrolytic pattern obtained when it is used as a substrate. A degree of hydrolysis between 64.7 % and 100 % has been determined in different tannic acid samples. The specific growth rate of 0.712 h−1, 0.792 h−1, 0.477 h−1, 0.536 h−1 for Jalmek®, Faga Lab®, Division Food®, and Riedel de Häen®, respectively, was obtained at the concentration of 80 g L−1 of each of the tannic acids.

Producción Fúngica de Proteasas Inducidas con Pelo de Cerdo

The production of new proteases induced with pig hair was evaluated using two systems, submerged culture and solid state culture. Culture medium was Czapek-Dox for both systems. Enzyme production kinetic was monitored each 24 hours during 120 hours. Protelytic activity was evaluated with the azocasein method and biomass production was determined by the gravimetric method. Rhizopus oryzae was the microorganism with the capacity of using the pig hair as the single carbonnitrogen source, producing in submerged fermentation the highest enzymatic titers. The effect of pH, the substrate pretreatment and addition of different levels of substrate on proteolyitic activity and biomass production were determined. Results permitted to obtain titers of proteolytic activity of 975 U/L.