Production, statistical optimization, and functional characterization of alkali stable pectate lyase of Paenibacillus lactis PKC5 for use in juice clarification.

Pectate lyase is a hydrolytic enzyme used by diverse industries to clarify food. The enzyme occupies a 25% share of the total enzyme used in food industries, and their demand is increasing gradually. Most of the enzymes in the market belong to the fungal origin and take more time to produce with high viscosity in the fermentation medium, limiting its use. The bacteria belonging to the genus Bacillus have vast potential to produce diverse metabolites of industrial importance. The present experiment aimed to isolate pectate lyase-producing bacteria that can tolerate an alkaline environment at moderate temperatures. Bacillus subtilis PKC2, Bacillus licheniformis PKC4, Paenibacillus lactis PKC5, and Bacillus sonorensis ADCN produced pectate lyase. The Paenibacillus lactis PKC5 gave the highest protein at 48 h of incubation that was partially purified using 80% acetone and ammonium sulphate. Purification with 80% acetone resulted in a good enzyme yield with higher activity. SDS-PAGE revealed the presence of 44 kDa molecular weight of purified enzyme. The purified enzyme exhibits stability at diverse temperature and pH ranges, the maximum at 50 °C and 8.0 pH. The metal ions such as Mg2+, Zn2+, Fe2+, and Co2+ significantly positively affect enzyme activity, while increasing the metal ion concentration to 5 mM showed detrimental effects on the enzyme activity. The organic solvents such as methanol and chloroform at 25% final concentration improved the enzyme activity. On the other hand, detergent showed inhibitory effects at 0.05% and 1% concentration. Pectate lyase from Paenibacillus lactis PKC5 had Km and Vmax values as 8.90 mg/ml and 4.578 µmol/ml/min. The Plackett-Burman and CCD designs were used to identify the significant process parameters, and optimum concentrations were found to be pectin (5 gm%) and ammonium sulphate (0.3 gm%). During incubation with pectate lyase, the clarity percentage of the grape juice, apple juice, and orange juice was 60.37%, 59.36%, and 49.91%, respectively.

Antibacterial properties of Apis dorsata honey against some bacterial pathogens.

Now-a-days, different bioproducts are being used extensively for the welfare of mankind. However, for proper utility of any bioproduct, the exact biotechnological potential of that product should be explored. Honey is produced in almost every country on the planet. It has long been used as a medicinal agent in addition to its broader use as a popular food throughout the human history. It can be used to treat various diseases without causing any negative side effects. In the present study, the antibacterial potential of honey produced by A. dorsata was investigated at its variable concentrations (25, 50, 75 and 100 %) against four pathogenic bacterial species. The highest antimicrobial action was seen against E. coli at 100 % concentration of the honey while showing zone of inhibition of 37.5 ±â€¯3.5 mm. However, the lowest antibacterial action was observed against E. faecalis. The overall order of growth inhibition by the honey at its 100 % concentration for the implicated bacterial species appeared as: E. coli ˃ P. aeruginosa ˃ S. aureus ˃ E. faecalis. The honey couldn't show antibacterial action at its 25 % concentration. Our findings of the present study will be helpful for utility of the honey as an alternative medicine for curing different complications caused by microbial pathogens.