Characterization of tannase activity in cell-free extracts of Lactobacillus plantarum CECT 748T

Production of recombinant glycosidases fused with Usp45 and SpaX to avoid the purification and immobilization stages

The elucidation of the physicochemical properties of glycosidases is essential for their subsequent technological application, which may include saccharide hydrolysis processes and oligosaccharide synthesis. As the application of cloning, purification and enzymatic immobilization methods can be time consuming and require a heavy financial investment, this study has validated the recombinant production of the set of Lacticaseibacillus rhamnosus fucosidases fused with Usp45 and SpaX anchored to the cell wall of Lacticaseibacillus cremoris subsp cremoris MG1363, with the aim of avoiding the purification and stabilization steps. The cell debris harboring the anchored AlfA, AlfB and AlfC fucosidases showed activity against p-nitrophenyl α-L-fucopyranoside of 6.11 ± 0.36, 5.81 ± 0.29 and 9.90 ± 0.58 U/mL, respectively, and exhibited better thermal stability at 50 °C than the same enzymes in their soluble state. Furthermore, the anchored AlfC fucosidase transfucosylated different acceptor sugars, achieving fucose equivalent concentrations of 0.94 ± 0.09 mg/mL, 4.11 ± 0.21 mg/mL, and 4.08 ± 0.15 mg/mL of fucosylgalatose, fucosylglucose and fucosylsucrose, respectively.

Comprehensive analysis of the metabolic and genomic features of tannin transforming Lactiplantibacillus plantarum strains

Extracellular tannase Lactiplantibacillus plantarum-producing strains (TanA+) release bioactive metabolites from dietary tannins. However, there is a paucity of knowledge of TanA+ strains and their hydrolyzing capacities. This study aimed to shed light on the metabolic and genomic features of TanA+ L. plantarum strains and to develop a screening technique. The established spectrophotometric was validated by UPLC-UV-QToF. Eight of 115 screened strains harbored the tanA gene, and six presented TanA activity (PROBI S126, PROBI S204, RKG 1-473, RKG 1-500, RKG 2-219, and RKG 2-690). When cultured with tannic acid (a gallotannin), TanA+ strains released 3.2-11 times more gallic acid than a lacking strain (WCFS1) (p < 0.05). TanA+ strains with gallate decarboxylase (n = 5) transformed this latter metabolite, producing 2.2-4.8 times more pyrogallol than the TanA lacking strain (p < 0.05). However, TanA+ strains could not transform punicalagin (an ellagitannin). Genomic analysis revealed high similarity between TanA+ strains, as only two variable regions of phage and polysaccharide synthesis were distinguished. A phylogenetic analysis of 149 additional genome sequences showed that tanA harboring strains form a cluster and present two bacteriocin coding sequences profile. In conclusion, TanA+ L. plantarum strains are closely related and possess the ability to resist and transform gallotannins. TanA can be screened by the method proposed herein.

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.

The Change Mechanism of Structural Characterization and Thermodynamic Properties of Tannase from Aspergillus niger NL112 Under High Temperature

Tannase from Aspergillus niger NL112 was purified 5.1-fold with a yield of 50.44% via ultrafiltration, DEAE-Sepharose Fast Flow column chromatography, and Sephadex G-100 column chromatography. The molecular weight of the purified tannase was estimated as 45 kDa. The optimum temperature and pH for its activity were 45 °C and 5.0, respectively. The results of circular dichroism, FT-IR (Fourier transform infrared) spectroscopy, and fluorescence spectra indicated that high temperature could lead to the change of tannase secondary and tertiary structures. Tannase had a greater affinity for tannic acid at 40 °C with a K_m value of 2.12 mM and the greatest efficiency hydrolysis (K_cat/K_m) at 45 °C. The rate of inactivation (k) increased with the increase of temperature and the half-life (t_1/2) gradually decreased. It was found to be 1.0 of the temperature quotient (Q₁₀) value for tannic acid hydrolysis by tannase. The thermodynamic parameters of the interaction system were calculated at various temperatures. The positive enthalpy (ΔH) values and decreasing ΔH values with the increase of temperature indicated that the hydrolysis of tannase was an endothermic process. Our results indicated that elevated temperature could change the tertiary structure of tannase and reduce its thermostability, which caused a gradual decrease of tannase activity with an increase in temperature.

Contributions of protein microenvironment in tannase industrial applicability: An in-silico comparative study of pathogenic and non-pathogenic bacterial tannase

Tannase is an inducible industrially important enzyme, produced by several microorganisms. A large number of bacteria have reported as tannase producers; however, some of them are pathogenic in nature. Therefore, it is quite uncertain whether the application of these tannase enzymes from such pathogenic bacteria is suitable for industries and human welfare. Till date, there is no clear evidence regarding which group of bacteria (non-pathogenic or pathogenic) is better suited for their application in the edge of industries with particular reference to the food industry. The present study is following the findings of the above queries. In this study, a large number of tannase protein sequences have been retrieved from the databases, including both non-pathogenic and pathogenic bacterial species. Physiochemical and evolutionary properties of those sequences have been evaluated. Results have shown that non-pathogenic bacterial tannase possesses a high number of acidic and basic amino acid residues as compared to their pathogenic counterparts. The acidic and basic amino acid residues of tannase provide unique microenvironment to it. In the other hand, the numbers of disorder forming residues are higher in tannase sequences of pathogenic bacteria. The study of tannase microenvironment leads in the formation of salt bridges, which finally favoring the stability and proper functioning of tannase. This is the first report of such observation on tannase enzyme using in silico approach. Study of the microenvironment concept will be helpful in protein engineering.

Fruits and fruit by-products as sources of bioactive compounds. Benefits and trends of lactic acid fermentation in the development of novel fruit-based functional beverages

Current awareness about the benefits of a balanced diet supports ongoing trends in humans towards a healthier diet. This review provides an overview of fruits and fruit-by products as sources of bioactive compounds and their extraction techniques, and the use of lactic acid fermentation of fruit juices to increase their functionality. Fruit matrices emerge as a technological alternative to be fermented by autochthonous or allochthonous lactic acid bacteria (LAB such as Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and other Lactobacillus species), and also as probiotic vehicles. During fermentation, microbial enzymes act on several fruit phytochemicals producing new derived compounds with impact on the aroma and the functionality of the fermented drinks. Moreover, fermentation significantly reduces the sugar content improving their nutritional value and extending the shelf-life of fruit-based beverages. The generation of new probiotic beverages as alternatives to consumers with intolerance to lactose or with vegan or vegetarian diets is promising for the worldwide functional food market. An updated overview on the current knowledge of the use of fruit matrices to be fermented by LAB and the interaction between strains and the fruit phytochemical compounds to generate new functional foods as well as their future perspectives in association with the application of nanotechnology techniques are presented in this review.

Tannase-Converted Green Tea Extract with High (-)-Epicatechin Inhibits Skeletal Muscle Mass in Aged Mice

The objective of this study was to investigate the effects of tannase-converted green tea extract on body composition, muscle oxidative stress-related factors, and differentiation-related factors. The mean bone-related parameters and body composition were determined by the live dual-energy X-ray absorptiometry (DEXA). Quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting were used to determine mRNA expression and protein levels, respectively. The results of total mass testing in the epicatechin control (EC) and middle concentration tannase-converted green tea extract (T₁) intake groups were not significantly different compared with those in the control group; however, the high-concentration tannase-converted green tea extract (T₂) group showed a significantly higher effect to the lean than that of all other groups (p < 0.05). The results of the assay of muscle differentiation-related genes indicated that the expression levels in the EC and T₁ groups (p < 0.05) and the expression levels in the T₂ group (p < 0.01) were significantly different in the bicep femoris compared with that in the control group. The results of the SOD gene assay indicate that the expression levels in the EC and T₁ groups (p < 0.05) and the expression level in the T₂ group (p < 0.01) were significantly different in the bicep femoris compared with that in the control group. Additionally, SOD gene expression in the T₂ group was significantly increased (p < 0.05) in the soleus compared with that in the control, EC and T₁ groups. Our results suggest that tannase-converted green tea extract prevents muscle loss and regulates the quantity and quality of muscle by the levels of antioxidant stress-related enzymes and muscle differentiation factors to a greater extent than the administration of epicatechin and middle dose green tea extract.

Expression and biochemical characterization of a new alkaline tannase from Lactobacillus pentosus

Lactobacillus pentosus BA-7 and L. pentosus QA1-5 are tannin-tolerant lactic acid bacteria that were isolated from Miang, a traditional fermented tea-leaf found in northern Thailand and a tannin-rich substrate. Tannase encoding genes were isolated, cloned and overexpressed in Escherichia coli BL21(DE3). The recombinant tannase was produced with production yields of 40 and 39 KU/L for LpTanBA-7 and LpTanQA1-5, respectively. Both revealed the same molecular weight of 50 kDa as estimated by SDS-PAGE and were optimally active under alkaline pH conditions LpTanQA1-5 revealed optimal temperatures in a range of 37-40 °C as is typically found in lactic acid bacteria, while LpTanBA-7 was active at higher temperatures with an optimum temperature range of 45-55 °C. LpTanBA-7 was found to be more stable within the same range of temperatures than LpTanQA1-5. Furthermore, it was active and stable toward various organic solvents and produced 50 mg/mL of gallic acid from 100 mg/mL tannic acid. Based on the results, LpTanBA-7 is considered a new alkali-moderately thermophilic tannase obtained from lactic acid bacterium that may be capable of a feasible production capacity of gallic acid and its esters. Furthermore, tannase that is active at high temperatures could also be used in tea products in order to develop a sweet aftertaste, as well as to improve levels of antioxidant activity.

Bacterial tannases: classification and biochemical properties

Tannin acyl hydrolases, also known as tannases, are a group of enzymes critical for the transformation of tannins. The study of these enzymes, which initially evolved in different organisms to detoxify and/or use these plant metabolites, has nowadays become relevant in microbial enzymology research due to their relevant role in food tannin transformation. Microorganisms, particularly bacteria, are major sources of tannase. Cloning and heterologous expression of bacterial tannase genes and structural studies have been performed in the last few years. However, a systematic compilation of the information related to all recombinant tannases, their classification, and characteristics is missing. In this review, we explore the diversity of heterologously produced bacterial tannases, describing their substrate specificity and biochemical characterization. Moreover, a new classification based on sequence similarity analysis is proposed. Finally, putative tannases have been identified in silico for each group of tannases taking advantage of the use of the "tannase" distinctive features previously proposed.

Lactic Acid Bacteria from Argentinean Fermented Foods: Isolation and Characterization for their Potential Use as Starters for Fermentation of Vegetables

Lactic acid bacteria (LAB) improve the organoleptic, nutritional and physicochemical properties of artisanal foods. In this study, we selected 31 fermented dairy and vegetable foods marketed in Tucumán city, Argentina, as sources of LAB for the production of pickles. Sixty-four isolates presumptively identified as Lactobacillus strains were screened for relevant technological properties for production of fermented foods. Most strains showed moderate to good acidification (>0.04 pH units/h) and proteolytic capabilities (free aminoacids >1 mmol/L), produced diacetyl and/or acetoin and were resistant to 4% NaCl. Based on acid production and osmotolerance, we selected six LAB strains and identified them by 16S rDNA sequencing (97–100% identity) as: Lactobacillus rhamnosus CRL2159 and CRL2164, L. plantarum CRL2161 and CRL2162, Weissella viridescens CRL2160 and W. paramesenteroides CRL2163. Relevant properties for pickle manufacturing were further assessed. At an initial pH=4.5 and 7% NaCl, L. plantarum CRL2162 and L. rhamnosus CRL2164 performed the best with high growth and inhibitory activity against Escherichia coli and Listeria innocua. There was no obvious antagonism among the selected strains that would dismiss their use in mixed cultures. Properties of the selected LAB suggest their potential as starter cultures for obtaining standardized, fermented vegetable products of high quality. The development of these new industrial starters would increase the competitiveness of production and open the country’s frontiers in the canned vegetable market.

Degradation of euptox A by tannase-producing rumen bacteria from migratory goats

AIMS

The gut microbiota capable of degrading plant biomass and antinutritional phytometabolites are of immense importance. This study reports isolation and characterization of tannase-producing rumen bacteria that could also degrade euptox A (9-oxo-10,11-dehydroageraphorone) present in Eupatorium adenophorum (Spreng).

METHODS AND RESULTS

Migratory Gaddi goats were selected as source of inoculums for isolating rumen bacteria with ability to produce tannase which catalyses degradation of hydrolysable tannins (HTs). Three rumen bacterial isolates producing tannase were studied, and identified as Klebsiella variicola strain PLP G-17 LC, K. variicola strain PLP S-18 and Klebsiella pneumoniae strain PLP G-17 SC. The isolates exhibited optimal tannase activity at 40°C, and pH 6·0. The bacteria could also degrade euptox A, a potent hepatotoxin in E. adenophorum Spreng, a widely distributed noxious weed.

CONCLUSIONS

The rumen bacteria could degrade antinutritional HTs and euptox A. Culture-independent metagenomic interventions are envisioned to completely decipher the rumen microbial ecology and exploit its genetic and metabolic potential.

SIGNIFICANCE AND IMPACT OF THE STUDY

The bacteria producing tannase which catalyses degradation of HTs, and concurrently degrading euptox A, may have potential as microbial feed additives to increase utilization of plant biomass containing antinutritional phytometabolites.

Gallic acid production under anaerobic submerged fermentation by two bacilli strains

BACKGROUND

Tannase is an enzyme that catalyses the breakdown of ester bonds in gallotannins such as tannic acid. In recent years, the interest on bacterial tannases has increased because of its wide applications. The lactic acid bacteria (LAB) plays an important role in food tannin biotransformation, it has the ability of hydrolyse tannins in ruminants intestine. The finding of tannin hydrolysis by LAB has sparked their use as tannase producer.

RESULTS

The bacterial strains used in the present work were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. The maximal tannase production levels were 1400 and 1239 U/L after 32 and 36 h of fermentation respectively, for B. subtilis AM1 and L. plantarum CIR1. Maximum gallic acid release was 24.16 g/L for B. subtilis AM1 and 23.73 g/L for L. plantarum CIR1. HPLC analysis showed the formation of another peaks in the retention time range of 9-14 min, which could be attributed to the formation of di or tri-galloyl glucose.

CONCLUSIONS

According to database, the strains were identified as Bacillus subtilis AM1 and Lactobacillus plantarum CIR1. In conclusion, both strains had the capability to produce good titres of extracellular tannase and release gallic acid.

Optimization of tannase production by a novel Klebsiella pneumoniae KP715242 using central composite design

A novel tannase producing bacterial strain was isolated from rhizospheric soil of Acacia species and identified as Klebsiella pneumoniae KP715242. A 3.25-fold increase in tannase production was achieved upon optimization with central composite design using response surface methodology. Four variables namely pH, temperature, incubation period, and agitation speed were used to optimize significant correlation between the effects of these variables on tannase production. A second-order polynomial was fitted to data and validated by ANOVA. The results showed a complex relationship between variables and response given that all factors were significant and could explain 99.6% of the total variation. The maximum production was obtained at 5.2 pH, 34.97 °C temperature, 103.34 rpm agitation speed and 91.34 h of incubation time. The experimental values were in good agreement with the predicted ones and the models were highly significant with a correlation coefficient (R²) of 0.99 and a highly significant F-value of 319.37.

Novel trends for use of microbial tannases

Tannases, mainly produced by microorganisms, are able to hydrolyze gallotannins, ellagitannins, complex tannins, and gallic acid esters into gallic acid, ellagic acid, glucose, or alcohols, and also synthesize gallic acid esters using tannic acid or gallic acid with a variety of alcohols in nonaqueous media. Microbial tannases have been widely applied especially in beverage processing, pharmaceutics, and brewing. However, many factors, especially high production costs, severely limit the use of microbial tannases at the industrial level. In this minireview, we aim to provide an overview of the advances in applications of microbial tannases during the last 15 years, mainly including the following respects: hydrolysis of tea cream, modification of green tea catechins, production of gallic acid, debittering of fruit juices, degradation of tannery effluents, and synthesis of propyl gallate, trying to know the trends and prospects for the future in applications of microbial tannases.

Immobilization of thermotolerant intracellular enzymes on functionalized nanoporous activated carbon and application to degradation of an endocrine disruptor: kinetics, isotherm and thermodynamics studies

Degradation of 2-nitro phloroglucinol using mixed intracellular enzymes immobilized FNAC matrix

Enhancement of tannase production by Lactobacillus plantarum CIR1: validation in gas-lift bioreactor

The optimization of tannase production by Lactobacillus plantarum CIR1 was carried out following the Taguchi methodology. The orthogonal array employed was L18 (2(1) × 3(5)) considering six important factors (pH and temperature, also phosphate, nitrogen, magnesium, and carbon sources) for tannase biosynthesis. The experimental results obtained from 18 trials were processed using the software Statistical version 7.1 using the character higher the better. Optimal culture conditions were pH, 6; temperature, 40 °C; tannic acid, 15.0 g/L; KH2PO4, 1.5 g/L; NH4Cl, 7.0 g/L; and MgSO4, 1.5 g/L which were obtained and further validated resulting in an enhance tannase yield of 2.52-fold compared with unoptimized conditions. Tannase production was further carried out in a 1-L gas-lift bioreactor where two nitrogen flows (0.5 and 1.0 vvm) were used to provide anaerobic conditions. Taguchi methodology allowed obtaining the optimal culture conditions for the production of tannase by L. plantarum CIR1. At the gas-lift bioreactor the tannase productivity yields increase 5.17 and 8.08-fold for the flow rates of 0.5 and 1.0 vvm, respectively. Lactobacillus plantarum CIR1 has the capability to produce tannase at laboratory-scale. This is the first report for bacterial tannase production using a gas-lift bioreactor.

Differential activities of fungi-derived tannases on biotransformation and substrate inhibition in green tea extract

Tannases are important enzymes in the antioxidant potential of tea leaves. In this study, we evaluated the effect of two tannases (T1 and T2) on biotransformation of tea polyphenols and antioxidative activities from catechins in green tea extract (GTE). The T1 tannase-catalyzed reaction was inhibited by the addition of >2.0% GTE substrate, whereas the T2-catalyzed reaction was not inhibited, even by addition of 5.0% GTE. Furthermore, the T1 tannase-catalyzed reaction was inhibited by addition of 10 mg mL(-1) EGCG, whereas the T2 tannase-catalyzed reaction did not display any inhibitory effect. These results indicate that T2 tannase was more tolerant than T1 tannase to substrate inhibition in degallation reactions. Specifically, the substrate EGCG (90,687.1 μg mL(-1)) was transformed into gallic acid (50,242.9 μg mL(-1)) and EGC (92,598.3 μg mL(-1)) after 1-h treatment with T2 tannase (500 U g(-1)). The tannase-mediated product displayed higher in vitro radical-scavenging activity than the control. IC50 value of GTE on ABTS and DPPH radicals (46.1 μg mL(-1) and 18.4 μg mL(-1), respectively) decreased markedly after T2 tannase treatment (to 35.8 μg mL(-1) and 15.1 μg mL(-1), respectively). These results indicate that T2 tannase treatment of GTE enhanced its radical-scavenging activity, an increase that was also observed in the reaction using EGCG substrate. Taken together, our results revealed that T2 tannase is more suitable for biotransformation of catechins in GTE than T1 tannase, and T2 treatment provides an enhanced radical-scavenging effect.

Comparison of three tannases cloned from closely related lactobacillus species: L. Plantarum, L. Paraplantarum, and L. Pentosus

BACKGROUND

Tannase (tannin acyl hydrolase, EC 3.1.1.20) specifically catalyzes the hydrolysis of the galloyl ester bonds in hydrolyzable tannins to release gallic acid. The enzyme was found not only in fungal species but also many bacterial species including Lactobacillus plantarum, L. paraplantarum, and L. pentosus. Recently, we identified and expressed a tannase gene of L. plantarum, tanLpl, to show remarkable differences to characterized fungal tannases. However, little is known about genes responsible for tannase activities of L. paraplantarum and L. pentosus. We here identify the tannase genes (i.e. tanLpa and tanLpe) of the above lactobacilli species, and describe their molecular diversity among the strains as well as enzymological difference between species inclusive of L. plantarum.

RESULTS

The genes encoding tannase, designated tanLpa and tanLpe, were cloned from Lactobacillus paraplantarum NSO120 and Lactobacillus pentosus 21A-3, which shared 88% and 72% amino acid identity with TanLpl, cloned from Lactobacillus plantarum ATCC 14917(T), respectively. These three enzymes could comprise a novel tannase subfamily of independent lineage, because no other tannases in the databases share significant sequence similarity with them. Each of tanLpl, tanLpa, and tanLpe was expressed in Bacillus subtilis RIK 1285 and recombinant enzymes were secreted and purified. The K(m) values of the enzymes on each galloyl ester were comparable; however, the k(cat)/K(m) values of TanLpa for EGCg, ECg, Cg, and GCg were markedly higher than those for TanLpl and TanLpe. Their enzymological properties were compared to reveal differences at least in substrate specificity.

CONCLUSION

Two tannase genes responsible for tannase activities of L. paraplantarum and L. pentosus were identified and characterized. TanLpl, TanLpa and TanLpe forming a phylogenetic cluster in the known bacterial tannase genes and had a limited diversity in each other. Their enzymological properties were compared to reveal differences at least in substrate specificity. This is the first comparative study of closely related bacterial tannases.

Biosynthesis, structural architecture and biotechnological potential of bacterial tannase: a molecular advancement

Tannin-rich materials are abundantly generated as wastes from several agroindustrial activities. Therefore, tannase is an interesting hydrolase, for bioconversion of tannin-rich materials into value added products by catalyzing the hydrolysis of ester and depside bonds and unlocked a new prospect in different industrial sectors like food, beverages, pharmaceuticals, etc. Microorganisms, particularly bacteria are one of the major sources of tannase. In the last decade, cloning and heterologous expression of novel tannase genes and structural study has gained momentum. In this article, we have emphasized critically on bacterial tannase that have gained worldwide research interest for their diverse properties. The present paper delineate the developments that have taken place in understanding the role of tannase action, microbial sources, various cultivation aspects, downstream processing, salient biochemical properties, structure and active sites, immobilization, efforts in cloning and overexpression and with special emphasis on recent molecular and biotechnological achievements.

Tannin degradation by a novel tannase enzyme present in some Lactobacillus plantarum strains

Lactobacillus plantarum is frequently isolated from the fermentation of plant material where tannins are abundant. L. plantarum strains possess tannase activity to degrade plant tannins. An L. plantarum tannase (TanBLp, formerly called TanLp1) was previously identified and biochemically characterized. In this study, we report the identification and characterization of a novel tannase (TanALp). While all 29 L. plantarum strains analyzed in the study possess the tanBLp gene, the gene tanALp was present in only four strains. Upon methyl gallate exposure, the expression of tanBLp was induced, whereas tanALp expression was not affected. TanALp showed only 27% sequence identity to TanBLp, but the residues involved in tannase activity are conserved. Optimum activity for TanALp was observed at 30°C and pH 6 in the presence of Ca(2+) ions. TanALp was able to hydrolyze gallate and protocatechuate esters with a short aliphatic alcohol substituent. Moreover, TanALp was able to fully hydrolyze complex gallotannins, such as tannic acid. The presence of the extracellular TanALp tannase in some L. plantarum strains provides them an advantage for the initial degradation of complex tannins present in plant environments.

Tannase-converted green tea catechins and their anti-wrinkle activity in humans

BACKGROUND

This study was performed to investigate the anti-wrinkle effects of topical applications of green tea extract with high antioxidant activity by tannase treatment. Increases in gallic acid (GA), (-)-epigallocatechin (EGC), and (-)-epicatechin (EC) were observed in the green tea extract after tannase treatment.

OBJECTIVES

This study was performed to investigate the anti-wrinkle effects of topical applications of green tea extract exhibiting high antioxidant activity after tannase treatment.

METHODS

Subjects, randomly divided into two groups, received the application of either tannase-converted green tea extract (TGE) or normal green tea extract (NGE) on their crow's feet for 8 weeks. The anti-wrinkle effects were evaluated with two methods: (i) self-assessment; and (ii) average roughness of skin surface (R(a), R(z), and R(t) value) using skin replica and Skin-Visiometer SV 600.

RESULTS

The scavenging abilities of TGE against radicals were significantly higher compared to NGE. The evaluation of skin wrinkle index values after 8 weeks of treatment showed that reductions of R(a), R(z), and R(t) values in the TGE group were significantly greater than in the NGE group, which indicated that tannase treatment improved the anti-wrinkle effects of green tea extract. According to the overall ratings for wrinkle treatment by applying the formulations, most of the TGE group (63.60%) reported marked or moderate improvement in wrinkles compared with only 36.30% of the NGE group.

CONCLUSION

Tannase treatment can improve the antioxidant activity of green tea extract, conferring anti-wrinkle activities. These results suggest that TGE may have beneficial properties as an anti-wrinkle agent.

Some factors affecting tannase production by Aspergillus niger Van Tieghem

One variable at a time procedure was used to evaluate the effect of qualitative variables on the production of tannase from Aspergillus niger Van Tieghem. These variables including: fermentation technique, agitation condition, tannins source, adding carbohydrates incorporation with tannic acid, nitrogen source type and divalent cations. Submerged fermentation under intermittent shaking gave the highest total tannase activity. Maximum extracellular tannase activity (305 units/50 mL) was attained in medium containing tannic acid as tannins source and sodium nitrate as nitrogen source at 30 °C for 96 h. All added carbohydrates showed significant adverse effects on the production of tannase. All tested divalent cations significantly decreased tannase production. Moreover, split plot design was carried out to study the effect of fermentation temperature and fermentation time on tannase production. The results indicated maximum tannase production (312.7 units/50 mL) at 35 °C for 96 h. In other words, increasing fermentation temperature from 30 °C to 35 °C resulted in increasing tannase production.

Tannic acid-dependent modulation of selected Lactobacillus plantarum traits linked to gastrointestinal survival

BACKGROUND

Owing to its antimicrobial properties dietary tannins may alter the functional efficacy of probiotic lactobacilli in the gastrointestinal (GI)-tract influencing their growth, viability and molecular adaptation to the intestinal environment.

METHODS AND FINDINGS

The effects of tannic acid on Lactobacillus plantarum WCFS1 were studied by in vitro growth monitoring and visualizing the morphological alteration on the cell wall using transmission electron microscopy. Growth upon tannic acid was characterized by dose-dependent reductions of initial viable counts and extended lag phases. Lag phase-cells growing upon 0.5 mM tannic acid were abnormally shaped and experienced disturbance on the cell wall such as roughness, occasional leakage and release of cell debris, but resumed growth later at tannic acid concentrations high as 2.5 mM. To gain insight on how the response to tannic acid influenced the molecular adaptation of L. plantarum to the GI-tract conditions, gene expression of selected biomarkers for GI-survival was assessed by RT-qPCR on cDNA templates synthetized from mRNA samples obtained from cells treated with 0.5 or 2 mM tannic acid. Tannic acid-dependent gene induction was confirmed for selected genes highly expressed in the gut or with confirmed roles in GI-survival. No differential expression was observed for the pbp2A gene, a biomarker negatively related with GI-survival. However PBP2A was not labeled by Bocillin FL, a fluorescent dye-labeled penicillin V derivative, in the presence of tannic acid which suggests for enhanced GI-survival reportedly associated with the inactivation of this function.

CONCLUSIONS

Probiotic L. plantarum WCFS1 is able to overcome the toxic effects of tannic acid. This dietary constituent modulates molecular traits linked to the adaptation to intestinal environment in ways previously shown to enhance GI-survival.

Oriented covalent immobilization of enzymes on heterofunctional-glyoxyl supports

Novel heterofunctional glyoxyl-agarose supports were prepared. These supports contained the maximal concentration of glyoxyl groups to promote maximization of covalent immobilization and groups' capability to adsorb proteins by various mechanisms (e.g., ionic exchange, metal-chelate formation). Immobilization on various supports makes it possible to orientate and rigidify an enzyme in various regions of its surface. The use of different heterofunctional supports allowed for obtaining catalysts with different activity, stability, and selectivity properties.

Probiotic metabolites as epigenetic targets in the prevention of colon cancer

Dietary interventions for preventing colon cancer have recently attracted increased attention from researchers and clinicians. The probiotics have emerged as potential therapeutic agents but are also regarded as healthy dietary supplements for nutrition and health applications. The probiotic metabolome may interfere with various cellular and molecular processes, including the onset and progression of colon cancer. Probiotic metabolites may lead to the modulation of diverse cellular signal transduction and metabolic pathways. The gut microbial metabolites (organic acids, bacteriocins, peptides, etc.) have been noted to interact with multiple key targets in various metabolic pathways that regulate cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis, and metastasis. Progress in this field suggests that epigenetic alterations will be widely used in the near future to manage colon cancer. The present review provides insights into the molecular basis of the therapeutic applications and the chemopreventive activities of certain probiotic metabolites, with emphasis on the interaction between these metabolites and the molecular signaling cascades that are considered to be epigenetic targets in preventing colon cancer.

Novel strategies for upstream and downstream processing of tannin acyl hydrolase

Tannin acyl hydrolase also referred as tannase is an enzyme with important applications in several science and technology fields. Due to its hydrolytic and synthetic properties, tannase could be used to reduce the negative effects of tannins in beverages, food, feed, and tannery effluents, for the production of gallic acid from tannin-rich materials, the elucidation of tannin structure, and the synthesis of gallic acid esters in nonaqueous media. However, industrial applications of tannase are still very limited due to its high production cost. Thus, there is a growing interest in the production, recovery, and purification of this enzyme. Recently, there have been published a number of papers on the improvement of upstream and downstream processing of the enzyme. These papers dealt with the search for new tannase producing microorganisms, the application of novel fermentation systems, optimization of culture conditions, the production of the enzyme by recombinant microorganism, and the design of efficient protocols for tannase recovery and purification. The present work reviews the state of the art of basic and biotechnological aspects of tannin acyl hydrolase, focusing on the recent advances in the upstream and downstream processing of the enzyme.

Isolation and characterization of a novel tannase from a metagenomic library

A novel gene (designated as tan410) encoding tannase was isolated from a cotton field metagenomic library by functional screening. Sequence analysis revealed that tan410 encoded a protein of 521 amino acids. SDS-PAGE and gel filtration chromatography analysis of purified tannase suggested that Tan410 was a monomeric enzyme with a molecular mass of 55 kDa. The optimum temperature and pH of Tan410 were 30 °C and 6.4. The activity was enhanced by addition of Ca(2+), Mg(2+) and Cd(2+). In addition, Tan410 was stable in the presence of 4 M NaCl. Chlorogenic acid, rosmarinic acid, ethyl ferulate, tannic acid, epicatechin gallate and epigallocathchin gallate were efficiently hydrolyzed by recombinant tannase. All of these excellent properties make Tan410 an interesting enzyme for biotechnological application.

Inhibitory spectra and modes of antimicrobial action of gallotannins from mango kernels (Mangifera indica L.)

This study investigated the antimicrobial activities and modes of action of penta-, hexa-, hepta-, octa-, nona-, and deca-O-galloylglucose (gallotannins) isolated from mango kernels. The MICs and minimum bactericidal concentrations (MBCs) against food-borne bacteria and fungi were determined using a critical dilution assay. Gram-positive bacteria were generally more susceptible to gallotannins than were Gram-negative bacteria. The MICs of gallotannins against Bacillus subtilis, Bacillus cereus, Clostridium botulinum, Campylobacter jejuni, Listeria monocytogenes, and Staphylococcus aureus were 0.2 g liter(-1) or less; enterotoxigenic Escherichia coli and Salmonella enterica were inhibited by 0.5 to 1 g liter(-1), and lactic acid bacteria were resistant. The use of lipopolysaccharide mutants of S. enterica indicated that the outer membrane confers resistance toward gallotannins. Supplementation of LB medium with iron eliminated the inhibitory activity of gallotannins against Staphylococcus aureus, and siderophore-deficient mutants of S. enterica were less resistant toward gallotannins than was the wild-type strain. Hepta-O-galloylglucose sensitized Lactobacillus plantarum TMW1.460 to hop extract, indicating inactivation of hop resistance mechanisms, e.g., the multidrug resistance (MDR) transporter HorA. Carbohydrate metabolism of Lactococcus lactis MG1363, a conditionally respiring organism, was influenced by hepta-O-galloylglucose when grown under aerobic conditions and in the presence of heme but not under anaerobic conditions, indicating that gallotannins influence the respiratory chain. In conclusion, the inhibitory activities of gallotannins are attributable to their strong affinity for iron and likely additionally relate to the inactivation of membrane-bound proteins.

Characterization of lactic acid bacteria from musts and wines of three consecutive vintages of Ribeira Sacra

AIMS

This study was designed to isolate and characterize the lactic acid microbiota of the musts and wines of a young denomination of origin area, Ribeira Sacra in north-west Spain.

METHODS AND RESULTS

Over three consecutive years (2007, 2008 and 2009), we examined musts and wines from four cellars in different zones of the region. Through biochemical and genetic tests, 459 isolates of lactic acid bacteria (LAB) were identified as the following species: Lactobacillus alvei (0·7%), Lactobacillus brevis (1·7%), Lactobacillus frumenti (0·9%), Lactobacillus kunkeei (12%), Lactobacillus plantarum (6·5%), Lactobacillus pentosus (0·9%), Lactococcus lactis ssp. lactis (3%), Leuconostoc citreum (0·7%), Leuconostoc fructosum (synon. Lactobacillus fructosum) (3·7%), Leuconostoc mesenteroides ssp. mesenteroides (2·8%), Leuconostoc pseudomesenteroides (0·2%), Oenococcus oeni (59%), Pediococcus parvulus (7%) and Weisella paramesenteroides (synon. Leuconostoc paramesenteroides) (0·9%). Of these species, O. oeni was the main one responsible for malolactic fermentation (MLF) in all cellars and years with the exception of Lact. plantarum, predominant in 2007, in one cellar, and Lact. brevis, Lact. frumenti and Ped. parvulus coexisting with O. oeni in one cellar in 2009. Different strains (84) of LAB species (14) were identified by biochemical techniques (API strips, the presence of plasmids, enzyme activities and MLF performance) and molecular techniques (PCR). All assays were carried out with every one of the 459 isolates. To select candidates for use as culture starters, we assessed malolactic, β-glucosidase and tannase activities, the presence of genes involved in biogenic amine production and plasmid content.

CONCLUSIONS

A high diversity of LAB is present in the grape musts of Ribeira Sacra but few species are responsible for MLF; however, different strains of such species are involved in the process. As far as we are aware, this is the first report of Lact. frumenti thriving in wine.

SIGNIFICANCE AND IMPACT OF THE STUDY

Information on LAB populations in must and wine is presented. A large collection of well-characterized strains of LAB are available as starter cultures to winemakers.