Background and objective: Biodiversity of yeasts in extreme habitats and applications in food industry attract many of researchers. The aim of this study was evaluation of invertase activity in isolated yeasts from saline soil.Material and Methods: In this study, kinetic activity of invertase from 27 halophilic and halotolerant yeast strains isolated from salin soil of Qom and Arak were evaluated. After collection of soil samples, the yeasts were cultured on YPD Agar containing 5% salt. Out of 27 yeast strains, 2 halophilic and 6 halotolerant strains with invertase activity were assessed for selection of best strain.Results: Assessment of invertase activity according to the Glucose Oxidase assay showed that the enzyme productivity of G5 strain is more powerful than other isolates. The optimum enzyme activity was obtained at 65oC and pH 4.5. The highest enzymatic activity was observed in the medium containing 1.7mM sodium chloride. Na+, Mg2+ and Ca2+ ions (all chlorides and 5mM concentration) have stimulation effect on enzyme's activity. The Km of enzyme for sucrose was 20 mM. Thermal stability of enzyme in 65oC was one hour and decrease of activity is not observed.Conclusion: According to the results of this study, G5 strain has able to produce invertase in different concentrations of different salts.

Background: In Algeria the date wastes production is estimated at least 85.000 tones. Date wastes is an economic source of carbohydrates for conversion to industrial enzymes because it is readily available and relatively low priced.Objective: The aim of the present study was to investigate the potential of using date wastes as a substrate for the production of a-amylase and invertase.Materials and Methods: Thirty strains of A. niger were isolated from the saline soils collected from five arid locations in Algeria. The process parameters; time, temperature, sugar content, initial pH, nitrogen source, nitrogen and phosphorus content, in the production of these enzymes were optimized.Results: The obtained results showed the potential of the Aspergillus niger for level productions of these enzymes. For a- amylase production, the cumulative effect of fermentation period of 96 h, temperature of 30oC, sugar content of 20 g/L, initial pH 5.5, supplemented with yeast extract as nitrogen source, and yeast extract and potassium phosphate at 5.0 g/L, content during the fermentation process of date wastes syrup produced a-amylase levels up to 285.6 U/ml. Invertase was produced up to 195.56 U/ml were produced under optimum conditions of 96 h, temperature of 30oC, initial pH 6.0, sugars content of 40.0 g/L and the utilization of yeast extract and potassium phosphate at concentrations of 11.0 and 3.5 g/L, respectively.Conclusions: The results obtained, provided evidences, supporting the potential of date waste as suitable source for production of a-amylase and invertase at industrial scale.

Aims Invertase is an enzyme that is widely used in industries. The main source of industrial production of invertase is yeast Saccharomyces cerevisiae (S. cerevisiae). Increasing thermal stability makes an important contribution to improving productivity in related production. The aim of this study was increasing thermal stability of Saccharomyces cerevisiae recombinant protein invertase by site-directed mutagenesis. Materials & Methods In the present experimental study, using invertase enzyme from thermophilic bacteria, Thermotoga maritima as template, it was decided to replace the threonine 345 and asparagine 349 amino acid with alanine, using site-directed mutagenesis and in Pichia pastoris, cloning was performed with the SOEing polymerase chain reaction. The activity of natural and mutant recombinant invertase enzymes at different temperatures, different pHs, stability duration, and thermal-performance stability, and Michaelis– Menten kinetics were drawn. Findings The thermal-structural stability of the natural and mutant invertease enzymes at 55° C showed that the mutant enzyme had a higher thermal stability at 55° C compared with the natural enzyme. Both natural and mutant enzymes exhibited a similar trend in functional stability. Reduction of Km and increase of Vmax in sucrose substrate and 5-fold increase in Kcat/ Km ratio of mutant enzyme was observed. Conclusion Site-directed mutagenesis has no negative effect on the amount of production as well as the secretion of recombinant protein invertase and increases enzyme activity. The mutant enzyme has a higher structural stability than the natural enzyme without altering its functional stability.

Introduction: Invertase belongs to the class of enzymes called glycosidase. The enzyme is responsible for the catalytic hydrolysis of sucrose to release monosaccharides known as invert sugars. The aim of this study was the isolation, purification, and physicochemical properties of intracellular invertase from palm wine yeast (Saccharomyces sp.) as an alternative enzyme in several industrial applications.Materials and Methods: The yeast was harvested from the palm wine through flocculation and the intracellular invertase was isolated from the yeast cell by mechanical grinding using acid washed sand. The intracellular invertase was purified using combination of ion-exchange chromatography on DEAE-trisacryl and gel filtration on Sephacryl S-300. The kinetics and other physicochemical properties of the purified enzyme were determined.Results: The two-step purification scheme employed gave a final yield of 168% and a purification fold of 3.0. Denaturing polyacrylamide gel electrophoresis (SDS-PAGE) of the intracellular invertase gave six subunits with the molecular mass of 73.5 ± 2.1 kDa, 52.3 ± 8.1 kDa, 48.6 ± 3.0 kDa, 37.4 ± 4.8 kDa, 26.5 ± 3.6, and 24 ± 4.3 kDa, respectively, while non-denaturing PAGE revealed the presence of single entity invertase with the molecular mass of 267 kDa. Also, native molecular mass estimated on calibrated Sephacryl S-300 was 266 ± 28 kDa, revealing that the purified palm wine Saccharomyces invertase (PWSInv) is heterohexameric in nature. The Km and Vmax of the purified invertase were 30.8 ± 3.2 mM and 9672 ± 169.0 units/mg protein, respectively, leading to catalytic efficiency, kcat/Km of 1.43 × 106 M-1 s-1. The optimum temperature and pH were 60 °C and 3.0, respectively. The activation energy (Ea) of the intracellular invertase for the hydrolysis of sucrose was estimated to be 280.42 kJ/mol.Conclusions: The study established the presence of intracellular invertase from palm wine yeast and investigated some properties and characteristics of the purified invertase, which could be exploited for several biotechnological and industrial processes.

Background and Objective: Invertase enzyme or D-fructofuranosidfructohydrolase EC (3. 2. 1. 26) is a member of the hydrolase family and responsible for the decomposition of sucrose into fructose and glucose. In recent years, extensive research has been carried out to increase the industrial production of invertase enzyme. Material and Methods: This study focused on maximizing invertase production in Saccharomyces cerevisiae by optimizing culture media conditions. Elements of the culture media were investigated using monofunctional optimization method. Moreover, basic salt culture media, containing compounds such as Na₂HPO₄, K₂HPO₄, MgSO₄ and CaCl₂, were used. Then, growth curve of the yeast was plotted and results showed that the highest growth rate occurred within 38 h and the strongest enzyme activity occurred within 18 h. Optimizing the culture conditions showed that yeast provided the most activity with 1% sucrose as a carbon source, urea and 0. 5% meat peptone as nitrogen sources, pH 5, 30 °C and shaking speed of 150 rpm. In this research, 3-l fermentor was used to assess yeast growth and enzyme activity at a larger scale. Results and Conclusion: Results of this study showed that the highest OD value was included at 48 h and the highest enzyme activity was recorded at 28 and 96 h. The difference between the time of maximum growth and peak enzyme activity indicated the need of careful control of fermentation time to prevent unnecessary biomass accumulation. Therefore, further research in the field of advanced fermentation and optimization of yeast strains can help researchers achieve the highest secretion and enzyme activity.