Efficient tannase production using Brazilian citrus residues and potential application for orange juice valorization

Microbial tannases: biosynthesis, purification, characterization and potential industrial applications

Tannases are a family of esterases that catalyze the hydrolysis of ester and depside bonds present in hydrolyzable tannins to release glucose and gallic acid. This enzyme is widely spread in animals, plants, and microbes. In particular, fungi and bacteria are the major sources of tannase. In recent years, this enzyme has drawn the attention of investigators owing to its widespread emerging applications in different food, beverage, animal feed, pharmaceutical, and tannery effluent degradation processes. During the last decade, over-expression of the tannase gene and structural activity has gained momentum. This research focused on microbial tannases, which have sparked interest due to their various properties. The current study investigates the sources of tannase-producing microorganisms, the mechanisms of tannin metabolism, and the microbe's degradation of natural tannins. Furthermore, researchers proposed tannase's biochemical properties, cloning, expression, and structural construction. This review will help better understand microbial tannases for several important industrial and environmental applications.

High Concentrate Flavonoids Extract from Citrus Pomace Using Enzymatic and Deep Eutectic Solvents Extraction

This paper evaluated methodologies for extracting phenolic compounds by DES (Deep eutectic solvents) associated with pectinlyase. Citrus pomace was characterized chemically, and seven DESs were formulated for extraction. Two groups of extractions were performed. Group 1 extractions were performed only with DESs, at 40 °C and 60 °C, with CPWP (Citrus pomace with pectin) and CPNP (Citrus pomace no pectin). In group 2, the DES was associated with pectinlyase and used only with CPWP at 60 °C in two ways of extraction: E1S (one-step extraction) and E2E (2-step extraction). The extracts were evaluated TPC (total phenolic compounds), individual phenolic compounds by HPLC, and antioxidant capacity by methodologies of DPPH and FRAP. The results of group 1 extractions for CPWP showed the highest phenolic compounds concentration (559.2 ± 2.79 mg/100 g DM) at 60 °C. Group 2 (E2S) showed high values of total phenolic compounds (615.63 ± 28.01 mg/100 g DM) and antioxidant activity (23,200 ± 721.69 µmol TE/g DM), with values higher than conventional extraction (545.96 ± 26.80 mg/100 g DM and 16,682.04 ± 2139 µmol TE/g DM). The study demonstrated the excellent extractive potential of DES for flavonoid extraction from citrus pomace. DES 1 and 5 by E2S showed the highest phenolic compounds and antioxidant capacity values, mainly when associated with pectinlyase.

Sustainable Technological Methods for the Extraction of Phytochemicals from Citrus Byproducts

Citrus fruits are products of great market values, as used by the juice industry in huge quantities. The juice industry processes millions of tons of citrus fruits per year, but only the pulp is utilized, whereas peels, seeds, and membrane residues are mostly discarded. This generates vast amounts of byproducts (>100 million tons/year), since the peel can make up to 50% of the weight of the fresh fruit. Phytochemical investigations showed that citrus peels are great sources of bioactive compounds, e.g., phenolic compounds, carotenoids, and monoterpenes. These compounds could find numerous applications in the food, cosmetics, and pharmaceutical industries. The recovery of the phytochemicals would provide economic and environmental benefits. Researchers worldwide have developed innovative techniques to recover phytochemicals from the citrus waste, by endorsing the international waste-prevention policies. This chapter reviews the advances in the sector of food technology applied to citrus chemistry and describes the available green techniques that allow the recovery of phytochemicals from citrus byproducts.

A comprehensive review on tannase: Microbes associated production of tannase exploiting tannin rich agro-industrial wastes with special reference to its potential environmental and industrial applications

Microorganisms have been used for the production of various enzymes, including inducible tannase for various industrial and environmental applications. Tannases have lot of potential to convert hydrolysable tannins to gallic acid, which is one of the important industrial and therapeutic significant molecules whose demand is over 10000 tons per year. Tannins invariably occur in angiosperms, gymnosperms and pteridophytes, and predominantly present in various parts of plants such as, leaves, roots, bark and fruit. Furthermore, tannery effluents are frequently loaded with significant levels of tannic acid. Tannase can be effectively used to decrease tannin load in the toxic tannery effluent thus providing the opportunity to minimize the operational cost. Over the past three decades, tannase from microbial sources has been proposed for the degradation of natural tannins. The availability of various agro-industrial residues paves a way for maximum utilization of tannase production for the degradation of tannin and eventually the production of gallic acid. In this review, an illustrative and comprehensive account on tannase from microbial source for current day applications is presented. The present review emphasises on up-to-date microbial sources of tannases, biochemical properties, optimization of tannase production in solid state and submerged fermentation and its industrial and environmental applications.

Changes Over the Fermentation Period in Phenolic Compounds and Antioxidant and Anticancer Activities of Blueberries Fermented by Lactobacillus plantarum

This study determined the effects of blueberry fermentation by Lactobacillus plantarum on antioxidant and anticancer activities. The fermented blueberries extracted with 80% ethanol (FBE) showed increased superoxide dismutase-like activity, increased scavenging of DPPH and alkyl radicals, and increased antiproliferative activity against human cervical carcinoma HeLa cells by inducing apoptosis. Seven representative phenolic compounds (malvidin 3-O-glucopyranoside, gallic acid, protocatechuic acid, catechol, chlorogenic acid, syringic acid, and epigallocatechin) in FBE were measured by high-performance liquid chromatography at different fermentation times. The content of each phenolic compound in the FBE was dependent on the fermentation period. Protocatechuic acid and catechol levels increased significantly with fermentation time. Of these three major compounds (protocatechuic acid, catechol, and chlorogenic acid), catechol showed the most significant anticancer activity when HeLa cells were treated with each of these three compounds alone or mixed in various ratios. Pearson's product-moment correlation analysis revealed that the increases in antioxidant and anticancer activities following blueberry fermentation were positively correlated with the phenolic acids present in FBE. PRACTICAL APPLICATION: Blueberries fermented with a tannase-producing lactic acid bacteria (LAB), Lactobacillus plantarum showed higher antioxidant activities and antiproliferative activities against human cervical carcinoma HeLa cells than did raw blueberries. L. plantarum fermentation biotransformed blueberry polyphenols into active phenol metabolites with strong antioxidant and antiproliferative activities. Our results suggest that fermented blueberries are rich in phenolic acids, which are a promising source of natural antioxidants and anticancer drugs and can be used as additives in food, pharmaceuticals, and cosmetic preparations.

Simultaneous extraction and biotransformation process to obtain high bioactivity phenolic compounds from Brazilian citrus residues

Recent studies have pointed to a reduction in the incidence of some cancers, diabetes, and neuro-degenerative diseases as a result of human health benefits from flavanones. Currently, flavanones are obtained by chemical synthesis or extraction from plants, and these processes are only produced in the glycosylated form. An interesting environmentally friendly alternative that deserves attention regarding phenolic compound production is the simultaneous extraction and biotransformation of these molecules. Orange juice consumption has become a worldwide dietary habit and Brazil is the largest producer of orange juice in the world. Approximately half of the citrus fruit is discarded after the juice is processed, thus generating large amounts of residues (peel and pectinolytic material). Hence, finding an environmentally clean technique to extract natural products and bioactive compounds from different plant materials has presented a challenging task over the last decades. The aim of this study was to obtain phenolics from Brazilian citrus residues with high bioactivity, using simultaneous extraction (cellulase and pectinase) and biotransformation (tannase) by enzymatic process. The highest hesperetin, naringenin and ellagic acid production in the experiment were 120, 80, and 11,250 µg g(-1), respectively, at 5.0 U mL(-1) of cellulase and 7.0 U mL(-1) of tannase at 40°C and 200 rpm. Also, the development of this process generated an increase of 77% in the total antioxidant capacity. These results suggest that the bioprocess obtained innovative results where the simultaneous enzymatic and biotransformatic extracted flavanones from agro-industrial residues was achieved without the use of organic solvents. The methodology can therefore be considered a green technology.