Enhancement of acid amylase production by an isolated Aspergillus awamori

The differences in carbohydrate utilization ability between six rounds of Sauce-flavor Daqu

Sauce-flavor Daqu is an important source of fermentation power in baijiu brewing. Revealing carbohydrate metabolism will help to explore the underlying reasons for the difference in fermentation performance of Daqu. In this study, metagenomic and metaproteomic technologies were performed to explore the carbohydrate metabolism network and its active functional microorganisms of Sauce-flavor Daqu. The sugar profile was analyzed using LC-MS to confirm the metabolic network. The results showed that 23 fungi and 5 bacteria were involved in carbohydrate metabolism. Starch metabolism, cellulose metabolism, and glucan metabolism were the main metabolic pathways, in which fungi especially Aspergillus were more involved than bacteria. Among these active microorganisms, Saccharomycopsis fibuligera, Aspergillus oryzae, Monascus purpureus, Byssochlamys spectabilis, Lichtheimia ramosa, Thermomyces lanuginosus, and Thermoascus aurantiacus were significant functional microorganisms with the ability to produce multiple enzymes. Lichtheimia ramosa, Lichtheimia corymbifera and Kroppenstedtia eburnea were biomarkers of Daqu in the first round, granting it a better liquefaction ability. β-amylase derived from wheat also played an important role in starch degradation, and the synergistic effect with α-amylase endowed Daqu with higher liquefaction power in the first two rounds. The results of this study are of great significance for the analysis of the mechanism of Daqu fermentation and provide a reliable theoretical basis for strengthening the fermentation performance of Daqu.

Pilot-scale production of a highly thermostable α-amylase enzyme from Thermotoga petrophila cloned into E. coli and its application as a desizer in textile industry

In this study, the industrial applications of a highly thermostable α-amylase as a desizer in the textile industry was evaluated. The cloned gene was expressed in different media (ZBM, LB, ZYBM9, and ZB) with IPTG (isopropyl β-d-1-thiogalactopyranoside) used as an inducer. Lactose was also used as an alternate inducer for the T7 promoter system in E. coli. For the large-scale production of the enzyme, different parameters were optimized. The maximum enzyme production was achieved when the volume of medium was 70% of the total volume of fermenter with a 2.0 vvm air supply and 20% dissolved oxygen at a 200 rpm agitation rate. Under all the optimized conditions, the maximum enzyme production was 22.08 U ml⁻¹ min⁻¹ with lactose (200 mM) as an inducer in ZBM medium. The desizing potential of the purified α-amylase enzyme was calculated with different enzyme concentrations (50–300 U ml⁻¹) at different temperatures (50–100 °C), and pHs (4–9) with varying time intervals (30–120 min). The highest desizing activity was found when 150 U ml⁻¹ enzyme units were utilized at 85 °C and at 6.5 pH for 1 h.

Thermostable recombinant α-amylase was produced in a large scale for the desizing of cotton cloth in the textile industry.

Bioprospection and characterization of the amylolytic activity by filamentous fungi from Brazilian Atlantic Forest

Abstract Filamentous fungi are widely diverse and ubiquitous organisms. Such biodiversity is barely known, making room for a great potential still to be discovered, especially in tropical environments - which are favorable to growth and species variety. Filamentous fungi are extensively applied to the production of industrial enzymes, such as the amylases. This class of enzymes acts in the hydrolysis of starch to glucose or maltooligosaccharides. In this work twenty-five filamentous fungi were isolated from samples of decomposing material collected in the Brazilian Atlantic Forest. The two best amylase producers were identified as Aspergillus brasiliensis and Rhizopus oryzae. Both are mesophilic, they grow well in organic nitrogen-rich media produce great amounts of glucoamylases. The enzymes of A. brasiliensis and R. oryzae are different, possibly because of their phylogenetical distance. The best amylase production of A. brasiliensis occurred during 120 hours with initial pH of 7.5; it had a better activity in the pH range of 3.5-5.0 and at 60-75°C. Both fungal glucoamylase had wide pH stability (3-8) and were activated by Mn2+. R. oryzae best production occurred in 96 hours and at pH 6.5. Its amylases had a greater activity in the pH range of 4.0-5.5 and temperature at 50-65ºC. The most significant difference between the enzymes produced by both fungi is the resistance to thermal denaturation: A. brasiliensis glucoamylase had a T50 of 60 minutes at 70ºC. The R. oryzae glucoamylase only had a residual activity when incubated at 50°C with a 12 min T50.

Production of α-1,4-glucosidase from Bacillus licheniformis KIBGE-IB4 by utilizing sweet potato peel

In the current study, sweet potato peel (Ipomoea batatas) was observed as the most favorable substrate for the maximum synthesis of α-1,4-glucosidase among various agro-industrial residues. Bacillus licheniformis KIBGE-IB4 produced 6533.0 U ml^-1 of α-1,4-glucosidase when growth medium was supplemented with 1% dried and crushed sweet potato peel. It was evident from the results that bacterial isolate secreted 6539.0 U ml^-1 of α-1,4-glucosidase in the presence of 0.4% peptone and meat extract with 0.1% yeast extract. B. licheniformis KIBGE-IB4 released 6739.0 and 7190.0 U ml^-1 of enzyme at 40 °C and pH 7.0, respectively. An improved and cost-effective growth medium design resulted 8590.0 U ml^-1 of α-1,4-glucosidase with 1.3-fold increase as compared to initial amount from B. licheniformis KIBGE-IB4. This enzyme can be used to fulfill the accelerating demand of food and pharmaceutical industries. Further purification and immobilization of this enzyme can also enhance its utility for various commercial applications. Graphical abstract Pictorial representation of maltase production from sweet potato peel.

AmyM, a Novel Maltohexaose-Forming α-Amylase from Corallococcus sp. strain EGB

A novel α-amylase, AmyM, was purified from the culture supernatant of Corallococcus sp. strain EGB. AmyM is a maltohexaose-forming exoamylase with an apparent molecular mass of 43 kDa. Based on the results of matrix-assisted laser desorption ionization-time of flight mass spectrometry and peptide mass fingerprinting of AmyM and by comparison to the genome sequence of Corallococcus coralloides DSM 2259, the AmyM gene was identified and cloned into Escherichia coli. amyM encodes a secretory amylase with a predicted signal peptide of 23 amino acid residues, which showed no significant identity with known and functionally verified amylases. amyM was expressed in E. coli BL21(DE3) cells with a hexahistidine tag. The signal peptide efficiently induced the secretion of mature AmyM in E. coli. Recombinant AmyM (rAmyM) was purified by Ni-nitrilotriacetic acid (NTA) affinity chromatography, with a specific activity of up to 14,000 U/mg. rAmyM was optimally active at 50°C in Tris-HCl buffer (50 mM; pH 7.0) and stable at temperatures of <50°C. rAmyM was stable over a wide range of pH values (from pH 5.0 to 10.0) and highly tolerant to high concentrations of salts, detergents, and various organic solvents. Its activity toward starch was independent of calcium ions. The Km and Vmax of recombinant AmyM for soluble starch were 6.61 mg ml(-1) and 44,301.5 μmol min(-1) mg(-1), respectively. End product analysis showed that maltohexaose accounted for 59.4% of the maltooligosaccharides produced. These characteristics indicate that AmyM has great potential in industrial applications.

Optimization of selective production media for enhanced production of xylanases in submerged fermentation by Thielaviopsis basicola MTCC 1467 using L16 orthogonal array

Enzymes have been the centre of attention for researchers/industrialists worldwide due to their wide range of physiological, analytical, food/feed and industrial based applications. Among the enzymes explored for industrial applications, xylanases play an instrumental role in food/feed, textile/detergent, paper and biorefinery based application sectors. This study deals with the statistical optimization of xylanase production by Thielaviopsis basicola MTCC 1467 under submerged fermentation conditions using rice straw, as sole carbon source. Different fermentation parameters such as carbon source, nitrogen source, inorganic salts like KH2PO4, MgSO4 and pH of the medium were optimized at the individual and interactive level by Taguchi orthogonal array methodology (L16). All selected fermentation parameters influenced the enzyme production. Rice straw, the major carbon source mainly influenced the production of xylanase (~34 %). After media optimization, the yield of enzyme improved from 38 to ~60 IU/ml (161.5 %) indicating the commercial production of xylanase by T. basicola MTCC 1467. This study shows the potential of T. basicola MTCC 1467 for the efficient xylanase production under the optimized set of conditions.

Kinetics of rapamycin production by Streptomyces hygroscopicus MTCC 4003

Research work was carried out to describe the kinetics of cell growth, substrate consumption and product formation in batch fermentation of rapamycin using shake flask as well as laboratory-scale fermentor. Fructose was used as the sole carbon source in the fermentation media. Optimization of fermentation parameters and reliable mathematical models were used for the maximum production of rapamycin from Streptomyces hygroscopicus MTCC 4003. The experimental data for microbial production of rapamycin fitted well with the proposed mathematical models. Kinetic parameters were evaluated using best fit unstructured models, viz. Andrew's model, Monod model, Yano model, Aiba model. Andrew's model showed a comparatively better R² value (0.9849) among all tested models. The values of maximum specific growth rate (μ_max), saturation constant (K_S), inhibition constant (K_i), and growth yield coefficient (Y_X/S) were found to be 0.008 (h^-1), 2.835 (g/L), 0.0738 (g/L), and 0.1708 (g g^-1), respectively. The optimum production of rapamycin was obtained at 300 rpm agitation and 1 vvm aeration rate in the fermentor. The final production of rapamycin in shake flask was 539 mg/L. Rapamycin titer found in bioreactor was 1,316 mg/L which is 52 % higher than the latest maximum value reported in the literature.

Multiresponse Optimization of Inoculum Conditions for the Production of Amylases and Proteases by Aspergillus awamori in Solid-State Fermentation of Babassu Cake

This work aimed at investigating the simultaneous production of amylases and proteases by solid-state fermentation (SSF) of babassu cake using Aspergillus awamori IOC-3914. By means of experimental design techniques and the desirability function, optimum inoculum conditions (C/N ratio of propagation medium, inoculum age, and concentration of inoculum added to SSF medium) for the production of both groups of enzymes were found to be 25.8, 28.4 h, and 9.1 mg g⁻¹, respectively. Significant influence of both initial C/N ratio and inoculum concentration was observed. Optimum amylolytic activities predicted by this multiresponse analysis were validated by independent experiments, thus indicating the efficacy of this approach.

Citrus peel influences the production of an extracellular naringinase by Staphylococcus xylosus MAK2 in a stirred tank reactor

Staphylococcus xylosus MAK2, Gram-positive coccus, a nonpathogenic member of the coagulase-negative Staphylococcus family was isolated from soil and used to produce naringinase in a stirred tank reactor. An initial medium at pH 5.5 and a cultivation temperature of 30°C was found to be optimal for enzyme production. The addition of Ca(+)² caused stimulation of enzyme activity. The effect of various physico-chemical parameters, such as pH, temperature, agitation, and inducer concentration was studied. The enzyme production was enhanced by the addition of citrus peel powder (CPP) in the optimized medium. A twofold increase in naringinase production was achieved using different technological combinations. The process optimization using technological combinations allowed rapid optimization of large number of variables, which significantly improved enzyme production in a 5-l reactor in 34 h. An increase in sugar concentration (15 g l⁻¹) in the fermentation medium further increased naringinase production (8.9 IU ml⁻¹) in the bioreactor. Thus, availability of naringinase renders it attractive for potential biotechnological applications in citrus processing industry.

Optimization of process parameters for the production of tyrosine phenol lyase by Citrobacterfreundii MTCC 2424

The process optimization using technological combinations for the production of tyrosine phenol lyase by Citrobacter freundii MTCC 2424 has been carried out in this study. The maximum production of tyrosine phenol lyase (0.15 U) was obtained by culturing C. freundii MTCC 2424 in a medium containing (g/l) meat extract 5.0, yeast extract 5.0, peptone 2.5, and l-tyrosine 1.0 at 25 degrees C for 16 h in a temperature controlled orbital shaker. A 2.5-fold increase in enzyme activity with 1.3-fold decrease in the cost of enzyme production (in terms of media components) was achieved by using different technological combinations. The process optimization using technological combinations allowed quick optimization of large number of variables, which helps in designing of suitable fermentation conditions for the cost-effective production of tyrosine phenol lyase. Moreover, this also provides information for balancing the nutrient concentration with minimum experimentation.