Production and Optimization of Xylanase and α-Amylase from Non-Saccharomyces Yeasts (Pichia membranifaciens)

Laser-induced changes in the gene expression, growth and development of Gladiolus grandiflorus cv. "White Prosperity"

Corms of Gladiolus grandiflorus cv. "White Prosperity" was irradiated via red laser at wavelength 635 nm. Various morphological, flowering, elemental and chemical characterizations were studied. Irradiation with different power (5, 20, and 50 mW) and various irradiation time (0.0, 0.5, 1, 3, 5 and 10 min) was studied. Several characters), totaletermined include vegetative growth parameter (spouting days, plant height (cm), leaves number, leaves fresh and dry weights (g/plant), diameter of plant middle part (mm) and leaf area (cm2), floral parameters (flowering days, vase life (day), fresh and dry weights of inflorescence (g/plant), number of flowers per inflorescence, inflorescence length(cm), flowers diameter(cm), number of corms per plant, corms fresh weight(g/plant), circumference/ corms), pigments [total chlorophylls in leaves (SPAD), anthocyanin content (mg/100 g F.W.) in petals], NPK (%) in new corms and chemical composition in corms; total carbohydrates (%),total phenol (μg CE/g (%),total flavonoid (μg CE/g) (%), antioxidant (DPPH IC50 (μg /ml (%), and proline content (μ moles/g). The results showed that the medium level (20 mW) of He-Ne laser at 5 min caused favorable changes in the leaf anatomical structures and other studied characters followed by the low level (5 mW) of He-Ne laser at 5min. 112 bands emerged from 22 SSR primers, ranging between 130 and 540 bp, with 32 bands having polymorphism ranging from 17-100%. Out of the 22 SSR primers, 3 primers exhibited a high polymorphism percentage, i.e., SSR6, SSR16 and SSR22 which exhibited 7 positive markers. These findings revealed the efficiency of SSR primers for differentiating gladiolus plants and revealed that some alleles were affected by laser in their corms and the expression resulted in color or abnormalities in leaves and/or flowers. Mutation in some alleles could result in abnormalities like mutation in the allele with 410 bp revealed by SSR16.

Extracellular enzymes producing yeasts study: cost-effective production of α-amylase by a newly isolated thermophilic yeast Geotrichum candidum PO27

Enzymes are biocatalysts mainly used for their industrial potential in various applications. The present study aims to understand the enzyme production for biotechnological interest from a local yeast strain. From 100 isolates obtained from various biotopes, 78 strains were selected for their enzymatic heritage. Screening of α-amylase, lipase/esterase, and cellulase activities by rapid plate detection methods was carried out and the PO27 yeast was selected for its high capacity to produce α-amylase. In addition, this yeast strain exhibited good lipolytic and esterolytic activities, as well as low cellulase activity. A sequence analysis of the D1/D2 region of the 26S ribosomal RNA (26S rRNA) and a study of morphological characteristics identified the PO27 strain as Geotrichum candidum. The production of α-amylase has been studied in solid medium fermentation using various natural substrates without any supplementation such as olive pomace, potato peels, leftover bread, and mastic cake. G. candidum PO27 showed an improved production of α-amylase with olive pomace, thus reaching approximately 180.71 U/g. To evaluate the ability of this isolate to produce α-amylase in submerged fermentation, multiple concentrations of olive pomace substrate were tested. The best activity of submerged fermentation was statistically compared to the solid-state fermentation result in order to select the appropriate fermentation type. A high significant difference was found to rank the 6% olive pomace medium as the best substrate concentration with 34.395 U/mL of α-amylase activity. This work showed that the new isolate Geotrichum candidum PO27 has a better potential to produce α-amylase at a low cost in solid-state fermentation compared to submerged fermentation. Optimization conditions for PO27 α-amylase production through solid-state fermentation were achieved ‎ using a one factor at a time (OFAT) approach. The findings revealed that a high temperature (60 °C), an acidic pH, malt extract, and soluble starch were the highly significant medium components for enhancing α-‎amylase production. The use of olive pomace waste by Geotrichum candidum PO27 is expected to be effective in producing an industrially useful α-amylase.

Characterization of thermo/halo stable cellulase produced from halophilic Virgibacillus salarius BM-02 using non-pretreated biomass

The production of extremozymes from halophilic bacteria has increased significantly due to their stability and efficiency in catalyzing a reaction, as well as their capacity to display optimum activity at various salt concentrations. In the current study, the halophilic bacterium Virgibacillus salarius strain BM-02 could utilize many non-pretreated substrates including cellulose, corn stover, sugarcane bagasse and wheat bran as a sole carbon source. However, wheat bran was the best substrate for achieving optimum saccharification yield (90.1%). The partially purified cellulase was active and stable at a wide range of pH (5-8) with residual activities > 58%. Moreover, it was stable at 5-12% of NaCl. Metal ions have a variable impact on the activity of partially purified cellulase however, Fe⁺³ exhibited the highest increase in the cellulase activity. The enzyme exhibited a thermal stability at 40, 50 and 60 °C with half-lives of 1049.50, 168.14 and 163.5 min, respectively. The value of V_max was 22.27 U/mL while Km was 2.1 mM. The activation energy of denaturation E_d 69.81 kJ/mol, the enthalpy values (ΔH_d) were positive, and the entropy values (ΔS) were negative. Therefore, V. Salarius is recommended as a novel promising halophilic extremozyme producer and agricultural waste remover in the bio-industrial applications.

Cellulolytic and Xylanolytic Enzymes from Yeasts: Properties and Industrial Applications

Lignocellulose, the main component of plant cell walls, comprises polyaromatic lignin and fermentable materials, cellulose and hemicellulose. It is a plentiful and renewable feedstock for chemicals and energy. It can serve as a raw material for the production of various value-added products, including cellulase and xylanase. Cellulase is essentially required in lignocellulose-based biorefineries and is applied in many commercial processes. Likewise, xylanases are industrially important enzymes applied in papermaking and in the manufacture of prebiotics and pharmaceuticals. Owing to the widespread application of these enzymes, many prokaryotes and eukaryotes have been exploited to produce cellulase and xylanases in good yields, yet yeasts have rarely been explored for their plant-cell-wall-degrading activities. This review is focused on summarizing reports about cellulolytic and xylanolytic yeasts, their properties, and their biotechnological applications.

Production of extracellular α-amylase by single-stage steady-state continuous cultures of Candida wangnamkhiaoensis in an airlift bioreactor

The kinetics of growth and α-amylase production of a novel Candida wangnamkhiaoensis yeast strain were studied in single-stage steady-state continuous cultures. This was performed in a split-cylinder internal-loop airlift bioreactor, using a variety of carbon sources as fermentation substrates. Results showed that the steady-state yields of cell mass from carbohydrates were practically constant for the range of dilution rates assayed, equaling 0.535 ± 0.030, 0.456 ± 0.033, and 0.491 ± 0.035 g biomass/g carbohydrate, when glucose, maltose, and starch, respectively were used as carbon sources. No α-amylase activity was detected when glucose was used as the carbon source in the influent medium, indicating that α-amylase synthesis of C. wangnamkhiaoensis is catabolically repressed by glucose. Contrastingly, maltose and starch induce synthesis of α-amylase in C. wangnamkhiaoensis, with starch being the best α-amylase inducer. The highest α-amylase volumetric and specific activities (58400 ± 800 U/L and 16900 ± 200 U/g biomass, respectively), and productivities (14000 ± 200 U/L·h and 4050 ± 60 U/g biomass·h, respectively) were achieved at a dilution rate of 0.24 h-1 using starch as the carbon source. In conclusion, single-stage steady-state continuous culture in an airlift bioreactor represents a powerful tool, both for studying the regulatory mechanisms of α-amylase synthesis by C. wangnamkhiaoensis and for α-amylase production. Furthermore, results showed that C. wangnamkhiaoensis represents a potential yeast species for the biotechnological production of α-amylase, which can be used for the saccharification of starch. This offers an attractive renewable resource for the production of biofuels (particularly bioethanol), representing an alternative to fossil fuels with reduced cost of substrates.

Production of Cocktail Enzymes by Three Cladosporium Isolates and Bioconversion of Orange Peel Wastes into Valuable Enzymes

The current research demonstrates the biotechnological economization of accumulated and inefficiently used agro-industrial orange peel wastes to generate amylase, endoglucanase, exoglucanase, pectinase, and xylanase, industrially essential enzymes with growing demands in enzyme markets, from three Cladosporium isolates. In submerged fermentation (SmF) at 10°C, the isolate AUMC 10865 produced the highest level of amylase (4164 IU/gram dry substrate). Endoglucanase, exoglucanase and xylanase had development peaks (923 IU/gds, 2280 IU/gds, and 1646 IU/gds, respectively in case of Cladosporium sp. AUMC 11366. Pectinase produced the most (7840 IU/gds) in the strain AUMC 11340. At 30°C, the strain AUMC 11340 secretes the most amylase (4120 IU/gds), endoglucanase (2700 IU/gds) and xylanase (3220 IU/gds). Exoglucanase development reached the peak (8750 IU/gds) in the isolate AUMC 10865. The overall production (5570 IU/gds) was instead enhanced by pectinase in the AUMC 11366 isolate. In solid-state fermentation (SSF) at 10°C, the isolate AUMC 10865 outperformed the other two isolates producing 640.0 IU/gds amylase, 763.3 IU/gds endoglucanase, 771.0 IU/gds exoglucanase, 1273.23 IU/gds pectinase and 1062.0 IU/gds xylanase, while the isolate AUMC 11366 produced the least amount of 399.7 IU/gds, 410.0 IU/gds, 413.3 IU/gds, 558.7 IU/gds, and 548.0 IU/gds, respectively. At 30°C, the isolate AUMC 11340 was superiorly producing higher levels of amylase (973.3 IU/gds), endoglucanase (746.0 IU/gds), exoglucanase (1052.0 IU/gds), pectinase (1685.3 IU/gds) and xylanase (1340.0 IU/gds), whereas isolate AUMC 10865 generated the least amounts of amylase (556.7 IU/gds) and exoglucanase (452.7 IU/gfs), and the isolate AUMC 11366 produced the least endoglucanase (256.3 IU/gds), pectinase (857.7 IU/gfs) and xylanase (436.3 IU/gds) amounts.