Skip to Main contentScienceDirectJournals BooksRegisterSign in Sign inRegisterJournals BooksHelpThermotoga neapolitanaRelated terms:FructoseMannitolTagatoseGalactoseGlucoseEnzymesIsomerasesThermotoga MaritimaArabinoseView all TopicsDownload as PDFSet alertAbout this pageBiomass Conversion of Plant ResiduesJoung Du Shin, ... Minsoo Kim, in Food Bioconversion, 20172.2 Anaerobic Digestion for Hydrogen ProductionDifferent straw-type lignocellulosic materials are widely examined as substrate for biohydrogen fermentations. Nguyen et al. (Nguyen et al., 2010) investigated the hydrogen production by using rice straw as substrate and Thermotoga neapolitana as producing microorganism in batch thermophilic (75°C) fermentations. They used thermal ammonia pretreatment—which has significant importance in delignification—and thermal dilute sulfuric acid treatment—to hydrolyze the hemicellulose fractions of rice straw—and combinations of the two. It could be concluded that the use of the combination of the two pretreatment methods was more effective than the single method. The optimal condition was 10 wt.% ammonium hydroxide soaking at 121°C for 10–60 min and after separation; the solid fraction was treated by 1 wt.% sulfuric acid for 50 min at the same temperature. The maintenance of these parameters resulted in 2.7 mmol/g of H2 yield from rice straw. The rice straw was pretreated with NaOH (7 wt.% for 24 h) and hydrolyzed by xylanase derived from further fermentation. The maximal hydrogen yield in the experiments was 0.76 mol/mol xylose in case of pretreated rice straw. In case of soybean straw, HCl acid treatment was found to be the most competent pretreatment method as described by Han et al. (2012) compared to alkaline, hydrogen peroxide, acid peroxide, and alkaline peroxide treatment. The boiling of the substrate for 30 min in 4 wt.% HCl proved to be the optimal choice based on the measurements covering the concentration scale from 0.5 to 8 wt.%. The optimizing strategy showed the peak hydrogen yield of 60.2 mL/g dry soybean straw, which is 11-fold higher than the case of untreated substrate.Nasirian et al. (2011) studied different types of pretreatment for biohydrogen fermentation from wheat straw, including fermentation without substrate treatment, acid pretreatment, and SHF and SSF methods. The acid treatment was carried out with 2 w/v % sulfuric acid at 120 °C for 90 min and the liquid fraction of the hydrolysis product was tested as fermentation substrate. For the purpose of enzyme hydrolysis, an enzyme mixture was used containing cellulase, xylanase, and glucanase. Mesophilic (36°C) fermentation showed a maximal hydrogen yield of 1.19 mol/mol glucose in case of acid pretreatment and 1 mol/mol glucose in case of SSF. Fan et al. (2006) investigated mesophilic bioH2 production by using raw and acid and microwave pretreated wheat straw and cow dung compost in batch experiments. It could be observed that substrate concentration, as well as acid concentration had a significant role regarding to the hydrogen yield, which has a maximal value of 68.1 mL/g TVS in case of 2 wt.% HCl and microwave treatment for 8 min and 25 g/L substrate concentration. This proved that efficient pretreatment methods and avoiding the inhibitor (which is discussed in the later sections) formation is necessary for the maximal H2 outputs.View chapterPurchase bookRead full chapterURL: https://www.sciencedirect.com/science/article/pii/B9780128114131000103Industrial Biotechnology and Commodity ProductsO.S. Ramos, F.X. Malcata, in Comprehensive Biotechnology (Second Edition), 20113.48.4.1.2 β-GlucanasesGlucan endo-β(1 → 3)-d-glucosidases, officially classified as endo-β(1 → 3)-glucanases (EC 3.2.1.39) and exo-β(1 → 3)-glucanases (EC 3.2.1.58), are widely distributed among higher plants, fungi, and bacteria. These enzymes catalyze hydrolysis of β(1 → 3)-glucosidic linkages in β(1 → 3)-d-glucan, which is the main constituent of fungal cell walls, besides a major structural and storage polysaccharide (laminarin) of marine macroalgae [7].The genes encoding endo-β(1 → 3)-glucanase from a variety of plants and bacteria (e.g., Bacillus circulans, Cellulomonas cellulans, Thermotoga neapolitana, Rhodothermus marinus, Arthrobacter spp., and Pyrococcus furiosus) have been sequenced, and eventually cloned in more suitable hosts [7]. Although the enzymes from either source can catalyze the same glucano hydrolysis reaction, bacterial enzymes are classified in the glycosyl hydrolase family 16 (GHF 16), whereas plant enzymes are grouped in GHF 17, based on differences found in their amino acid sequences.In foods, β-glucanases have been involved in defense against pathogenic fungi, via disruption of their cell walls. The application of β(1 → 3)-glucanases is also well established for preparation of protoplasts, and in degradation of the barley β-glucan that accumulates in the brewing process. Furthermore, such glucanases are important tools for use in yeast-based biotechnological processes, for example, cell fusion, transformation, and extraction of proteins.One important concern regarding the use of β-glucanases in plant-derived foods is that they usually contain various β(1 → 3)-d-glucans; these compounds are important in maintaining organoleptic properties, such as texture, viscosity, and appearance, so addition of exo-β(1 → 3)-glucanases may adversely affect these features [6].View chapterPurchase bookRead full chapterURL: https://www.sciencedirect.com/science/article/pii/B9780080885049002130CRISPRA. Golubov, in Genome Stability, 20168 Other Roles of the CRISPR/Cas SystemsThere is a growing body of evidence suggesting that the CRISPR/Cas system, besides its immunity function, can be a part of other cellular processes such as DNA repair and regulation of virulence.Taking in mind the ability of the CRISPR/Cas systems to shape a bacterial genome landscape by acquisition of new spacers, it was quite obvious to hypothesize that these systems might have an impact on the stability and evolution of bacterial genomes. Indeed, recent study of S. thermophilus revealed that the CRISPR/Cas systems target mobile genetic elements(bacteriophages, transposons, and plasmids), which likely contributed to gene acquisition and loss during evolutionary adaptation to milk, thus limiting genetic diversity and stabilizing of the S. thermophilus genome [71]. On the contrary, the genome analysis of T. maritima MSB8 and Thermotoga neapolitana NS-E provided evidence that the CRISPR/Cas systems might be a cause of numerous CRISPR-associated large-scale DNA rearrangements that destabilize and reshape genomes [72].It was shown that the Cas1 protein of E. coli interacts with RecB, RecC, and RuvB, it can process single-stranded and branched DNA species, replication forks and 5′ flaps [73]. In Francisella novicida, Cas9 protein uses a unique, small, CRISPR/Cas-associated RNA (scaRNA) to repress transcription of a bacterial lipoprotein (FTN_1103). As bacterial lipoproteins trigger a proinflammatory innate immune response in a host, CRISPR/Cas-mediated transcriptional repression of FTN_1103 is important for F. novicida to reduce this host response and promote virulence [74]. It has been demonstrated in Campylobacter jejuni that inactivation of the Type II CRISPR/Cas marker gene csn1 effectively reduced virulence in primarily cst-II-positive C. jejuni isolates [75]. cas2 mutants in Legionella pneumophila, although they grew typically in macrophages, were significantly impaired for infection of both Hartmannella and Acanthamoeba species. Given that infection of amebae is critical for L. pneumophila persistence in water systems, these data indicate that cas2 might play a role in the transmission of Legionnaires’ disease [76].To date, there is not enough data to draw a conclusion on whether the CRISPR/Cas systems are mainly involved in the bacterial immunity. Above-mentioned examples raise interesting questions about the evolution of CRISPR/Cas function, which require more in-depth research.View chapterPurchase bookRead full chapterURL: https://www.sciencedirect.com/science/article/pii/B9780128033098000069Bacteriophages, Part AAgnieszka Szczepankowska, in Advances in Virus Research, 20126 Classification of CRISPR/cas systemsA CRISPR repeat-spacer array, together with cas genes, constitutes an active CRISPR/cas system. First classification of CRISPR/cas systems based on Cas1 phylogenetic analysis and clustering of cas genes distinguished eight distinct subtypes—Ecoli, Ypest, Apern, Nmeni, Mtube, Tneap, Hmari, and Dvulg—identified respectively in specific strains of E. coli, Yersinia pestis, Aeropyrum pernix, Neisseria meningitis, Mycobacterium tuberculosis, Thermotoga neapolitana, Haloarcula marismortui, and Desulfovibrio vulgaris (Haft et al., 2005; Makarova et al., 2006). However, this classification now seems confusing in the light of increasing data on CRISPR/cas systems and their components, particularly that (i) CRISPRs often recombine, giving rise to hybrid systems; (ii) a single strain can have more than one CRISPR system; or (iii) CRISPR systems identified in various strains of the same species can vary. Currently, taking into account growing sequencing data on cas genes in various organisms and phylogenetic studies, a novel, more integrated classification of CRISPRs has been proposed (Makarova et al., 2011a,b). In effect, three main types (types I–III) of CRISPR/cas systems have been proposed, in all of which the central core is constituted by cas1 and cas2 genes. Moreover, each type of CRISPR/cas system is characterized by its specific signature genes, respectively, type I by cas3, type II by cas9, and type III by cas10 genes (Makarova et al., 2011a).In type I CRISPR/cas systems, apart from the cas3 gene, distinctive features are the cas4 gene and genes encoding for RAMPs—one protein from each of the three RAMP families (Cas5, Cas6, and Cas7). Type I systems are further divided into subtypes, which include I-A (Apern or CASS5), I-B (Tneap–Hmari or CASS7), I-C (Dvulg or CASS1), I-D, I-E (Ecoli or CASS2), and I-F (Ypest or CASS3). Specific subtypes are distinguished by another signature cas gene (cas8)—cas8a, cas8b, and cas8c, respectively, for subtypes I-A, I-B, and I-C.So far, type II CRISPR/cas systems have been identified solely in bacterial genomes and comprise two subtypes: II-A (Nmenni or CASS4) and II-B (Nmenni or CASS4a). Apart from the universally occurring cas1 and cas2 genes, the signature genes of type II systems are cas4 and cas9 (the latter previously termed csn1 or csx12).Type III CRISPR/cas systems are found most commonly in archaea. The signature genes encode for CRISPR polymerase (Cas10 with PALM domain) and RAMP proteins, including more than one Cas7-type protein and Cas6. Another signature gene specific for type III systems is cas10. Two subtypes of the type III CRISPR/cas systems have been recognized: subtype III-A (known otherwise as Mtube or CASS6) and subtype III-B (polymerase-RAMP module or Cmr system). Some type III systems lack cas1–cas2 genes, but in such cases they always co-occur with other CRISPR loci (type I or type II), which have been suggested to supply these genes in trans.Other CRISPR/cas systems that could not be classified to any of the three types are grouped as type U systems. In general, each subtype has been assigned a distinct signature gene, which defines and allows classification of individual CRISPR/cas systems (Makarova et al., 2011a). Subtypes for which signature genes have not been identified are defined as I-U, II-U, or III-U.View chapterPurchase bookRead full chapterURL: https://www.sciencedirect.com/science/article/pii/B978012394621800011XMicrobial Production of Low-Calorie SugarsFalguni Patra, ... Nihir Shah, in Microbial Production of Food Ingredients and Additives, 20175 Tagatosed-Tagatose, a stereoisomer of d-fructose, is a naturally occurring monosaccharide that is found in Sterculia setigera gum (Fig. 9.6). Sterilized cow’s milk, milk powder, and other dairy products have also been reported to contain tagatose in the 2–800 ppm range. It is almost as sweet as sucrose (92%) and has a calorific value of 1.5 kcal/g. Commercial tagatose is produced from lactose; lactose is enzymatically hydrolyzed to d-galactose, chemically isomerized under basic conditions, then purified by mineralization, ion exchange chromatography, and recrystallization. Tagatose has technological properties that are similar to traditional sugars and it can be used as a reducing sugar as it caramelizes at elevated temperatures; however, in contrast to traditional sugars, it is only partially absorbed by the body resulting in a reduced energy value. The major fraction of tagatose reaches the large intestine unabsorbed and this is where it undergoes fermentation. It is approved by US FDA and received GRAS status in 2002.Figure 9.6. Structure of Tagatose.Tagatose is used as a low-calorie sugar substitute in foods, beverages, and pharmaceutical products, but it is not suitable for people with hereditary fructose intolerance. Tagatose acts as a prebiotic and increases LAB numbers in human and animal gut, thereby providing functional benefits (Levin et al., 1995). It does not impart any laxative effect and is noncarcinogenic. The application of tagatose in beverages and foods plays an effective role in the management of diabetes, the control of dental carries, and in the control of calorific intake (Jayamuthunagai et al., 2016). Antioxidant and cryoprotective effects of tagatose are known to protect liver cells from lethal prooxidant poisons, such as cocaine and nitrofurantoin. Tagatose is well suited for confectionery products, such as chocolate, hard-boiled candies, fondant, fudge, and caramel due to its sweetness similarity with sucrose, its ability to crystallize, and its low-caloric value. It could also be used as a sucrose substitute in ice cream, soft drinks, and breakfast cereals.5.1 Biological Production of TagatoseTagatose can be produced by the oxidation of d-galactitol using microorganisms, such as Arthrobacter globiformis (Izumori et al., 1984), M. smegmatis (Izumori and Tsuzaki, 1988), Enterobacter agglomerans (Muniruzzaman et al., 1994), and G. oxydans (Manzoni et al., 2001; Rollini and Manzoni, 2005). The maximum yield from biotransformation has been reported as 92% (Muniruzzaman et al., 1994). However, this process cannot be used for the large-scale production of tagatose because of the high cost and unavailability of galactitol as a raw material. Tagatose production from psicose using various strains of Mucoraceae fungi have also been described (Yoshihara et al., 2006).Tagatose can also be manufactured by the enzymatic isomerization of d-galactose. Galactose can be obtained by the β-d-galactosidase-catalyzed hydrolysis of milk sugar lactose and subsequent separation into glucose and galactose. The enzyme l-arabinose isomerase (AI) catalyzes the in vitro conversion of galactose to tagatose and is therefore the most promising enzyme for the large-scale production of tagatose. Production of tagatose from galactose using AI is the most commercially feasible tagatose manufacturing process among the other biocatalysts.The biological production of tagatose from galactose using AI has been of great interest. AIs have been identified from a number of microorganisms including Thermotoga maritima (Kim et al., 2003b), Thermus sp. (Kim et al., 2003a), Geobacillus thermodenitrificans (Kim and Oh, 2005), Geobacillus stearothermophilus, Lb. plantarum NC8 (Chouayekh et al., 2007), Anoxybacillus flavithermus (Li et al., 2011), Arthrobacter sp. 22c (Wanaska and Kur, 2012), Bacillus stearothermophilus IAM 11001 (Cheng et al., 2010a), Acidothermus cellulolyticus (Cheng et al., 2010b), Lb. fermentum CGMCC2921 (Xu et al., 2011), L. sakei 23K (Rhimi et al., 2010), Pediococcus pentosaceus PC-5 (Men et al., 2014), and Pseudomonas aeruginosa PAO1 (Patel et al., 2016). E. coli cells expressing AI from Thermotoga neapolitana were immobilized in Ca-alginate beads. The resulting cell reaction, in continuous recycling mode at 70°C for 12 h, produced 49 and 38 g of tagatose/L from 180 and 90 g of galactose/L, respectively (Hong et al., 2007). Lim et al. (2008) studied tagatose production from galactose by T. neapolitana AI using chitopearl beads as immobilization supports. Tagatose production of 138 g/L was achieved from 300 g/L of galactose when a stirred-tank reactor containing the immobilized enzyme was used (70°C, pH 7.5). A high-yielding tagatose production process was also developed using alginate-immobilized Lb. fermentum CGMCC2921 cells (Xu et al., 2012). The immobilized cells isomerized galactose into tagatose at an optimum temperature and pH of 65°C and 6.5. Tagatose was also successfully obtained from lactose after a two-step biotransformation process using commercial β-galactosidase and immobilized Lb. fermentum cells. The relatively high conversion rate (60%) and productivity (11.1 g/L/h) of galactose to tagatose conversion were achieved in a packed-bed bioreactor. Salonen et al. (2013) overexpressed AI from Bifidobacterium longum NRRL B-41409 in L. lactis, and tagatose production from galactose was studied using recombinant resting L. lactis cells in the presence of a borate buffer. Tagatose production improved when high pH, temperature, and borate concentration were used. The use of 20 g/L of galactose at 37.5°C for 5 days resulted in 92% conversion of galactose into tagatose. When studied in 10 sequential 24 h batches (the production medium was changed every 24 h), a tagatose production rate of 185 g/L/day was achieved using 300 g/L of galactose and 1.15 M borate at 41°C. Rhimi et al. (2011) expressed B. stearothermophilus US100AI in Lactobacillus bulgaricus and Streptococcus thermophilus and reported that both strains produced tagatose from galactose during fermentation in laboratory media and milk. They also stated that addition of AI to milk allowed the conversion of galactose into tagatose during the fermentation process. Wanaska and Kur (2012) developed a single-step method for producing tagatose directly from whey permeates. They used a genetically modified P. pastoris expressing β-d-galactosidase from Arthrobacter chlorophenolicus and an engineered AI from psychrotolerant bacterium Arthrobacter sp. 22c. The combination of the recombinant yeast strain and the enzyme in one reaction mixture resulted in the hydrolysis of lactose (90%), the utilization of glucose, and the isomerization of galactose to tagatose (30%) simultaneously. In another study a novel biocatalyst for the production of tagatose was designed by displaying AI from Lb. fermentum CGMCC2921 on the surface of B. subtilis 168 spores (Liu et al., 2014). They reported that under optimum conditions the robust spores could convert 75% of galactose (100 g/L) into tagatose after 24 h and the conversion rate remained at 56% after the third cycle. Zhan et al. (2014) developed a single-step tagatose fermentation method by coexpressing the β-d-galactosidase gene (lacZ) and AI mutant gene (araA) in E. coli. They reported that the recombinant E. coli-ZY cells could hydrolyze more than 95% of the lactose and convert 43% of galactose into tagatose. Xu et al. (2016) also coexpressed an AI from Lb. fermentum CGMCC2921 and a β-galactosidase from Thermus thermophilus HB27 in E. coli. Under optimal conditions and whole cell biocatalysis, 101 g/L of tagatose was produced in 16 h with a productivity of 6.3 g/L/h and a yield of 20.2%.View chapterPurchase bookRead full chapterURL: https://www.sciencedirect.com/science/article/pii/B978012811520600009XBeta-Glucosidase From PenicilliumGustavo Molina, ... Gláucia M. Pastore, in New and Future Developments in Microbial Biotechnology and Bioengineering, 20187.6 Immobilization of β-GlucosidaseImmobilization is a promising tool used in both laboratory and industrial scale to optimize processes using a biocatalyst fixed in a support with no loss of activity. In recent years, its advantages compared with free biocatalysts, such as higher productivity, better stability, potential for reuse, resistance to inhibitors, and recovery of the product with high purity, have been noted (Eş et al., 2015; Romo-Sánchez et al., 2014). In general, different supports have been tested for β-glucosidases, including immobilization in polyvinyl alcohol Lentikats, sol–gel, calcium alginate, physical sorption on Eupergit C particles, Amberlite resins, covalent attachment to gelatin, and adsorption on concanavalin A-Sepharose within PGAG (propylene glycol alginate/bone gelatin) spheres (Figueira et al., 2011; Woodward and Capps, 1992). Many studies have also reported immobilization of β-glycosidases from diverse sources, such as almonds (Chen et al., 2014; Gómez et al., 2012; Guan et al., 2013; Zhu et al., 2016), Clostridium cellulolyticum (Honda et al., 2015), T. reesei (Borges et al., 2014), Thermotoga neapolitana (Khan et al., 2012), Thermoanaerobacterium thermosaccharolyticum (Zhao et al., 2013), Anaerocellum thermophilum (Chiang et al., 2013), Exiguobacterium sp. Chang et al. (2013), and A. niger (Ahmed et al., 2013; Alftrén and Hobley, 2013; González-Pombo et al., 2014; Javed et al., 2016; Romo Sánchez et al., 2015; Samaratunga et al., 2015; Tsai and Meyer, 2014; Verma et al., 2013).Unlike our expectations, it was found just a few 1980–90’s works with immobilization of β-glucosidases from Penicillium, what is surprising considering the potential of applications of their enzymes in different fields, as described in this chapter. In the first study, Rao et al. (1983) immobilized a β-glucosidase from P. funiculosum on polyamide using glutaraldehyde and compared its kinetic parameters, stability and reusability in assays using cellobiose, CMC (carboxymethyl cellulose), and pNPG (para-nitrophenyl-β-d-glucoside). While the Km and Vmax parameters did not improve with the form immobilized, there was 100% conversion of cellobiose and pNPG even after reusing the enzyme six times (Rao et al., 1983). One year later, these authors immobilized the same enzyme on a soluble polymer poly(vinyl alcohol) (PVA) and evaluated the kinetic parameters for CMC, filter paper, and pPNG substrates. The immobilization of β-glucosidase did not show an improvement in the affinity of the enzyme by the substrate and the Km values were similar in both forms of enzyme, free or PVA-immobilized (Rao and Mishra, 1984). They also carried out hydrolysis experiments using pure (cellulose powder and Solka-Floc) and complex (NaOH-treated bagasse) cellulosic substrates at two temperatures (37°C and 50°C) and three time points (4, 18, and 24 hours). The hydrolysis of pure cellulosic substrates was very similar with free and PVA-bound enzyme. The higher saccharification of bagasse at 37°C could be have been caused by the immobilization of β-glucosidase from P. funiculosum together with another component showing xylanase activity (Rao and Mishra, 1984).Later, Aguado et al. (1993) immobilized a β-glucosidase from P. funiculosum on nylon powder activated with glutaraldehyde, reaching 67% enzyme retention. They showed that the immobilized enzyme had significantly more thermal stability than the assays carried out with the free enzyme in the temperature range of 30–70°C. The immobilized enzyme did not have much loss of activity up to 50°C after 25 hours, decreasing its activity only at 60°C and 70°C. On the other hand, the free enzyme deactivated at 40°C (Aguado et al., 1995).To the best of our knowledge, no other study has used β-glucosidases from other Penicillium species and tried to immobilize it for any application. What seems to be more commonly investigated—at least in a number of publications—is the immobilization of naringinase, a debittering enzyme complex with high potential for application in food and pharmaceutical industries (Nunes et al., 2012). It has both α-rhamnosidase (EC 3.2.1.40) and β-glucosidase (EC 3.2.1.21) activity in two polypeptides of the same protein and can be produced by various microorganisms, including fungi, yeasts, and bacteria, e.g., A. niger, Aspergillus oryzae, Penicillium ulaiense, Penicillium decumbens, Pichia angusta, Williopsis californica, Staphylococcus xylosus, Clostridium stercorarium, and Lactobacillus plantarum (Chen et al., 2013; Puri and Banerjee, 2000; Puri, 2012; Ribeiro, 2011).Naringinase obtained from Penicillium sp. has been immobilized in different supports. Norouzian et al. (1999) immobilized the enzyme by entrapping it in calcium alginate beads, hen eggwhite, and gelatin and attached it to seeds of Ocimum basilicum in order to evaluate its potential on hydrolysis of naringin and fruit juice debittering. The optimum pH and temperature varied from 3.5 to 4.5 and 60°C to 65°C and the covalent attachment to seeds was the best method with 57% of the total enzyme activity and stability of 7 days (Norouzian et al., 1999). Using cellulose acetate films, Soares and Hotchkiss (1998) immobilized naringinase and tried to apply this method on an inner layer of a package to reduce the naringin concentration. The immobilized enzyme had an optimum pH higher than free enzyme (4.0 and 3.5) and a lower Km value (2.1 mM compared to 3.6 mM), indicating improvement of enzyme affinity for the naringin substrate. More recently, entrapment on PVA-DMSO particles, PVA-alginate beads, and covalent binding to woodchips aiming to immobilize naringinase for debittering of fruit juices has been performed (Nunes et al., 2010; Puri et al., 2005). Puri et al. (2005) immobilized naringinase from Penicillium sp. on glutaraldehyde-coated woodchips at 45°C and observed a significant increase in thermal stability of the enzyme, which was stable during storage at 4°C. Moreover, 76% debittering efficiency for kinnow mandarin juice using the form immobilized was attained.While naringinase is often used for the hydrolysis of naringin to remove the bittering of citrus juices, it can also be used for pharmaceutical applications. The flavonoid naringin found in citrus juices and released after hydrolysis of naringinase has shown antioxidant and anti-inflammatory activities, besides having an inhibitor effect on tumor development. Amaro et al. (2009) investigated the feasibility of immobilizing naringenase from P. decumbens on nonionic microstructured polymeric Amberlite support activated with different concentrations of glutaraldehyde, evaluated the naringin hydrolysis, and tested a diet with naringin and naringenin uptake as an alternative treatment for colitis in mice as animal model. An efficiency of 80% with the enzyme immobilized was obtained and it was possible to reuse it in five consecutive experiments. Compared with other methods and supports, the Km was lower (0.006 mmol L−1), which indicates an increase in affinity of the enzyme to substrate, even though the Vmax was lower than others works. Treatment with naringin and naringenin was found to have good results, since these flavonoids can reduce edema of the gut and have antiinflammatory activity (Amaro et al., 2009).View chapterPurchase bookRead full chapterURL: https://www.sciencedirect.com/science/article/pii/B9780444635013000077Archaeal hyperthermostable mannitol dehydrogenases: A promising industrial enzymes for d-mannitol synthesisMarwa Yagoub Farag Koko, ... Li Yang, in Food Research International, 20207.2 ThermodynamicsThermotoga neapolitana and Thermotoga maritima MtDHs had thermos-activities at temperatures ranging from 90 to 120 °C, and the temperature ranges of both enzymes were similar to those of their host strains; thus. Moreover, Thermotoga neapolitana MtDH does not lose its activity after incubation at 75 °C for 1 h, and half of its kinetic stability was retained after incubation for 1 h at 90 °C. In contrast, Thermotoga maritima MtDH maintains 10% of its initial activity after 4 h of exposure to 85 and 90 °C and retains 85% and 50% activity at 75 and 80 °C, respectively. The effects of temperature on the activities of both enzymes were determined by following the degradation of NADH at 5 to 15 min intervals 15 min in the d-fructose reduction direction reaction. In these experiments, Thermotoga neapolitana MtDH retained its activity and was active for an extended period in the reaction medium (Koko et al., 2016). In contrast, Lactobacillus intermedius MtDH had an optimum temperature of 37 °C and was inactivated after incubation at 50 °C for 30 min (Song et al., 2008).In general, thermophilic proteins have hydrophobic charged residues containing a smaller part of uncharged polar residues compared to mesophilic proteins (Rigoldi, Donini, Redaelli, Parisini, Gautieri, 2018). Increasing the enzyme s thermostability is the main factor that could affect the bioreactors in the industrial trail. The two enzymes can retain their thermos-function during the reaction; this makes both of them perfect catalysts for d-mannitol synthesis under high temperatures. The successful application of thermophilic and hyperthermophilic enzymes rely on their capability to retain dynamic characteristics under rigid conditions such as high temperatures, buffers concentration, chemical impurity, and pressure change (Vieille Zeikus, 2001).View articleRead full articleURL: https://www.sciencedirect.com/science/article/pii/S0963996920306633Recommended publicationsInfo iconFEBS LettersJournalBioresource TechnologyJournalSystematic and Applied MicrobiologyJournalFungal BiologyJournalBrowse books and journalsAbout ScienceDirectRemote accessShopping cartAdvertiseContact and supportTerms and conditionsPrivacy policyWe use cookies to help provide and enhance our service and tailor content and ads. By continuing you agree to the use of cookies.Copyright © 2021 Elsevier B.V. or its licensors or contributors. ScienceDirect ® is a registered trademark of Elsevier B.V.ScienceDirect ® is a registered trademark of Elsevier B.V.