Production of feed enzymes (phytase and plant cell wall hydrolyzing enzymes) byMucor indicus MTCC 6333: Purification and characterization of phytase

Mucoromycota fungi as powerful cell factories for modern biorefinery

Biorefinery employing fungi can be a strategy for valorizing low-cost rest materials, by-products and wastes into several valuable bioproducts through the fungal fermentation. Mucoromycota fungi are soil fungi with a highly versatile metabolic system that positions them as powerful microbial cell factories for biorefinery applications. Lipids, pigments, chitin/chitosan, polyphosphates, ethanol, organic acids and enzymes are main Mucoromycota products that can be refined from the fermentation process and applied in nutrition, chemical or biofuel industries. In addition, Mucoromycota biomass can be used as it is for specific purposes, such as feed. Mucoromycota fungi can be employed in developing co-production processes, whereby several intra- and extracellular products are simultaneously formed in a single fermentation process, and, thus, economic viability of the process can be improved. This mini review provides a comprehensive overview over the recent advances in the production of valuable metabolites by Mucoromycota fungi and fermentation strategies which could be potentially applied in the industrial biorefinery settings. KEY POINTS: • Biorefineries utilizing Mucoromycota fungi as production cell factories can provide a wide range of bioproducts. • Mucoromycota fungi are able to perform co-production of various metabolites in a single fermentation process. • Versatile metabolism of Mucoromycota allows valorization of a various low-cost substrates such as wastes and rest materials.

Optimization of solid-state fermentation for phytase production by Thermomyces lanuginosus using response surface methodology

A strain of Thermomyces lanuginosus, isolated from hot spring water in Turkey, was studied for optimization of phytase production using solid-state fermentation. Effects on fermentation of different production parameters such as substrate type, moisture, culture time, and inoculum size were investigated using a one-factor-at-a-time approach. Central composite design (CCD) of response surface methodology was applied for the optimization of four factors (culture temperature, initial pH, aeration area, age of seeding culture) that were affecting phytase production by Thermomyces lanuginosus in rice bran. Maximum phytase activity was achieved by using rice bran. The optimum levels of variables that supported maximum enzyme activity were moisture 70%, culture time 7 days, inoculum size 40%, culture temperature 55°C, initial pH 7.5, aeration area 30%, age of seeding culture 5 days, sucrose 1%, and ZnSO4 2.5 mM. An overall 10.83-fold enhancement in phytase activity (0.30 to 3.248 U) was attained due to the optimization.

Thermostable Alkaline Phytase from Alcaligenes sp. in Improving Bioavailability of Phosphorus in Animal Feed: In Vitro Analysis

A bacterial isolate, Alcaligenes sp. secreting phytase (EC 3.1.3.8), was isolated and characterized. The optimum conditions for the production of phytase included a fermentation period of 96 h, pH 8.0, and the addition of 1% (w/v) maltose and 1% (w/v) beef extract to the culture medium. This enzyme was purified to homogeneity and had an apparent molecular mass of 41 kDa. The optimum pH range and temperature for the activity of phytase were found to be 7.0-8.0 and 60°C, respectively. This enzyme was strongly inhibited by 0.005 M of Mn²⁺, Mg²⁺, and Zn²⁺. In vitro studies revealed that the phytase from Alcaligenes sp. released inorganic phosphate from plant phytates. Phytase released 1930 ± 28, 1740 ± 13, 1050 ± 31, 845 ± 7, 1935 ± 32, and 1655 ± 21 mg inorganic phosphate/kg plant phytates, namely, chick pea, corn, green pea, groundnut, pearl pea, and chick feed, respectively.

High level phytase production by Aspergillus niger NCIM 563 in solid state culture: response surface optimization, up-scaling, and its partial characterization

Phytase production by Aspergillus niger NCIM 563 was optimized by using wheat bran in solid state fermentation (SSF). An integrated statistical optimization approach involving the combination of Placket-Burman design (PBD) and Box-Behnken design (BBD) was employed. PBD was used to evaluate the effect of 11 variables related to phytase production, and five statistically significant variables, namely, glucose, dextrin, NaNO(3), distilled water, and MgSO(4) · 7H(2)O, were selected for further optimization studies. The levels of five variables for maximum phytase production were determined by a BBD. Phytase production improved from 50 IU/g dry moldy bran (DMB) to 154 IU/g DMB indicating 3.08-fold increase after optimization. A simultaneous reduction in fermentation time from 7 to 4 days shows a high productivity of 38,500 IU/kg/day. Scaling up the process in trays gave reproducible phytase production overcoming industrial constraints of practicability and economics. The culture extract also had 133.2, 41.58, and 310.34 IU/g DMB of xylanase, cellulase, and amylase activities, respectively. The partially purified phytase was optimally active at 55°C and pH 6.0. The enzyme retained ca. 75% activity over a wide pH range 2.0-9.5. It also released more inorganic phosphorus from soybean meal in a broad pH range from 2.5 to 6.5 under emulated gastric conditions. Molecular weight of phytase on Sephacryl S-200 was approximately 87 kDa. The K (m) and V (max) observed were 0.156 mM and 220 μm/min/mg. The SSF phytase from A. niger NCIM 563 offers an economical production capability and its wide pH stability shows its suitability for use in poultry feed.

Phytase from antarctic yeast strain Cryptococcus laurentii AL27

Cryptococcus laurentii strain AL27 demonstrating significant potential for intracellular phytase production was selected by 2-step screening of Antarctic yeasts. The strain showed increased phytase activity in a culture medium with 40 g/L sucrose, KH2PO4 providing 5 mg/L phosphorus, and cultivation temperature of 24 degrees C, which relates it to psychrotrophic microorganisms. The enzyme kinetic characteristics according to sodium phytate were Km = 0.98 mmol/L, vlim = 33.3 micromol g(-1) min(-1). The enzyme had maximum activity at 40 degrees C and acted within a wide pH range: from 2.0 to 5.5, which is of positive significance for its direct inclusion into the feed of monogastric animals.