Enhanced endoxylanase production by Myceliophthora thermophila using rice straw and its synergism with phytase in improving nutrition

Myceliophthora thermophila as promising fungal cell factories for industrial bioproduction: From rational design to industrial applications

Myceliophthora thermophila stands out as a prominent fungal cell factory, garnering growing interest due to its distinctive traits advantageous. Currently, M. thermophila has been developed as an efficient cell factory, producing a variety of products from various raw materials. In this review, we firstly discuss the potential advantages of M. thermophila as a platform for metabolic engineering and industrial applications, with special emphasis on its physiological characteristics, the development of genetic modification techniques and tools, gene expression and regulation strategies. Then, the latest progress in industrial application of M. thermophila as microbial cell factory was systematically summarized, including biochemical synthesis platform, enzyme expression platform, antibody protein and vaccine production platform, bio-organic fertilizer production platform, and efficient enzyme element library. Finally, the current challenges of M. thermophila as a cell factory and its corresponding strategies are proposed, aiming to achieve green biomanufacturing of multiple products with higher efficiency.

Optimization of phytase production by Penicillium oxalicum in solid-state fermentation for potential as a feed additive

The study aims to statistically optimize the phytase production by Penicillium oxalicum PBG30 in solid-state fermentation using wheat bran as substrate. Variables viz. pH, incubation days, MgSO4, and Tween-80 were the significant parameters identified through the Plackett-Burman design (PBD) that majorly influenced the phytase production. Further, central composite design (CCD) method of response surface methodology (RSM) defined the optimum values for these factors i.e., pH 7.0, 5 days of incubation, 0.75% of MgSO4, and 3.5% of Tween-80 that leads to maximum phytase production of 475.42 U/g DMR. Phytase production was also sustainable in flasks and trays of different sizes with phytase levels ranging from 394.95 to 475.42 U/g DMR. Enhancement in phytase production is 5.6-fold as compared to unoptimized conditions. The in-vitro dephytinization of feed showed an amelioration in the nutritive value by releasing inorganic phosphate and other nutrients in a time-dependent manner. The highest amount of inorganic phosphate (33.986 mg/g feed), reducing sugar (134.4 mg/g feed), and soluble protein (115.52 mg/g feed) was achieved at 37 °C with 200 U of phytase in 0.5 g feed for 48 h. This study reports the economical and large-scale production of phytase with applicability in enhancing feed nutrition.

Breeding of a thermostable xylanase-producing strain of Myceliophthora thermophila by atmospheric room temperature plasma (ARTP) mutagenesis

Introduction: Hemicellulose is an important component in lignocellulose materials, which is second only to cellulose, accounting for 15%-35% of the dry weight of plants. In the current situation of energy shortage, making full use of lignocellulose materials to produce fuel ethanol has become an important way to solve the energy problem. Xylanase plays a crucial role in the utilization of hemicellulose. It is a necessary means to reduce the cost of hemicellulose utilization by improving the activity of xylanase. Moreover, most naturally xylanases are mesophilic enzymes, which limits their industrial application. Methods:In this study, Myceliophthora thermophila was used to produce xylanases and a thermostable mutant M 2103 was obtained by atmospheric room temperature plasma (ARTP) mutagenesis. The research work started with exploring the effects of ARTP mutagenesis on the antioxidase system [superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), polyphenol oxidase (PPO), and antioxidant capacity (AOC)] of M. thermophile, and found that superoxide dismutase activity increased by 221.13%, and polyphenol oxidase activity increased by 486.04% as compared with the original strain when the implantation time was 300 s. So as to determine the conditions for subsequent mutagenesis. Results and Discussion:For the mutant M 2103, the reaction temperature for xylanase production remained stable in the range of 70°C-85°C. Its optimum temperature was 75°C, which was 15°C higher than that of the original strain. And its xylanase activity increased by 21.71% as compared with the original strain. M 2103 displayed a significantly higher relative xylanase activity than the original strain in the acidic (pH 4.0-7.0) range, and the xylanase activity was relatively stable in the pH range of 6.0-8.5. These results provide an alternative biocatalyst for the production of xylooligosaccharide, and a potential usage of ARTP in the mutagenesis of thermostable mutant.

Enhanced Phytase Production by Bacillus subtilis subsp. subtilis in Solid State Fermentation and its Utility in Improving Food Nutrition

BACKGROUND

Phytic acid acts as anti-nutritional factor in food and feed ingredients for monogastric animals as they lack phytases.

OBJECTIVE

Phytase production by Bacillus subtilis subsp. subtilis JJBS250 was studied in solid state fermentation and its applicability in dephytinization of food Methods: Bacterial culture was grown in solid state fermentation using wheat bran and various culture conditions were optimized using 'One variable at a time' (OVAT) approach. Effects of different substrates (wheat bran, wheat straw, sugarcane bagasse), incubation time (24, 48, 72 and 96 h), incubation temperatures (25, 30, 35 and 40 oC), pH (4.0, 5.0, 6.0, 7.0 and 8.0) and moisture content (1:1.5, 1:2.0, 1:2.5 and 1:3) were studied on phytase production. Bacterial phytase was used in dephytinization of food samples.

RESULTS

Optimization of phytase production was studied in solid state fermentation (SSF) using 'One variable at a time' (OVAT) approach. Bacillus subtilis subsp. subtilis JJBS250 grew well in various agroresidues in SSF and secreted high enzyme titres using wheat bran at 30 oC and pH 5.0 after incubation time of 48 h with substrate to moisture ratio of 1:3. Glucose and ammonium sulphate supplementation to wheat bran further enhanced phytase production in SSF. Optimization of phytase production resulted in 2.4-fold improvement in phytase production in solid state fermentation. The enzyme resulted in dephytinization of wheat and rice flours with concomitant release of inorganic phosphate, reducing sugar and soluble protein.

CONCLUSION

Optimization resulted in 2.34-fold enhancement in phytase production by bacterial culture that showed dephytinization of food ingredients with concomitant release of nutritional components. Therefore, phytase of B. subtilis subsp. subtilis JJBS250 could find application in improving nutritional quality of food and feed of monogastric animals.

Biosurfactants produced from corncob: a bibliometric perspective of a renewable and promising substrate

The reuse of agro-industrial waste has been a recurring issue since the 20th century. With a composition rich in carbohydrates and because of the massive amount of residue produced daily all over the world, corncob became a low-cost and suitable substrate to produce high added-value compounds. Biosurfactants are bioproducts of versatile applications due to their chemical structure with hydrophilic and hydrophobic regions. The current work performed a bibliometric analysis to identify research related to the synthesis of biosurfactants using corncob as substrate. Despite the high availability of corncobs, only nine articles were found in Scopus and Web of Science using different pretreatment processes and microorganisms. After an initial screening, data regarding research organizations, scientific journals, citations, countries, institutions, and keywords were analyzed. Results indicated that corncobs were also used to produce enzymes, adsorbents, activated carbon, and furfural. The presented evaluation updated the status of art, identifying a serious need for more research, especially because of corncob's high potential to provide fermentable sugars and the wide range of variables influencing fermentation processes that still need to be studied. A future association of this low-cost substrate with other methods can result in a promising scenario for technology transference.

Biochemical properties of cellulolytic and xylanolytic enzymes from Sporotrichum thermophile and their utility in bioethanol production using rice straw

Production of cellulolytic and xylanolytic enzymes by Sporotrichum thermophile was enhanced using response surface methodology in solid-state fermentation (SSF) using wheat straw and cotton oil cake. Cellulolytic and xylanolytic enzymes were partially purified by ammonium sulfate precipitation followed by ion exchange and gel filtration chromatographic techniques. Xylanase of S. thermophile is neutral xylanase displaying optimal activity at 60 °C with K_m and V_max values of 0.2 mg/mL and 238.05 µmole/min, respectively. All cellulases produced by the thermophilic mold showed optimal activity at pH 5.0 and 60 °C with K_m values of 0.312 mg/mL, 0.113 mg/mL, and 0.285 mM for carboxymethyl cellulase (CMCase), filter paper cellulase (FPase), and β-glucosidase, respectively and while V_max values were 181.81, 138.88, and 66.67 µmole/min, respectively. The presence of various metal ions (Ca²⁺ and Co²⁺), chemical reagent (glutaraldehyde), and surfactants (Tween 80 and Triton X-100) significantly improved the activities of all enzymes. All the enzymes showed high storage stability under low temperature (-20 and 4 °C) conditions. Cellulolytic and xylanolytic enzymes resulted in enhanced liberation of reducing sugars (356.34 mg/g) by hydrolyzing both cellulosic and hemicellulosic fractions of ammonia-pretreated rice straw as compared to other pretreatment methods used in the study. Fermentation of enzymatic hydrolysate resulted in the formation of 28.88 and 27.18 g/L of bioethanol in separate hydrolysis and fermentation (SHF) process by Saccharomyces cerevisiae and Pichia stipitis, respectively. Therefore, cellulolytic and xylanolytic enzymes of S. thermophile exhibited ideal properties of biocatalysts useful in the saccharification of cellulosic and hemicellulosic fractions of rice straw for the production of bioethanol.