Purification and characterization of a thermostable endo-beta-1,4 mannanase from Weissella viridescens LB37 and its application in fruit juice clarification

The isolation and characterization study of lactic acid bacteria was performed with a sample of fermented sausage, which was collected from a local market in Erzurum. As a result of sequencing analysis of 16S rRNA, this bacterium is found to be similar to Weissella viridescens (GenBank No: KM365459) at a ratio of 99 %. beta-Mannanase was purified 188.07 times from W. viridescens by using ammonium sulfate precipitation, ion exchange chromatography and then employing gel filtration chromatography techniques. The purified enzyme has shown only a protein band at a level of 36.25 kDa with SDS-PAGE. The mannanase obtained after these purification steps has shown maximum activity at pH 5 and 40 A degrees C, and the enzyme was determined to be quite stable within the range of pH 2-11 when temperature is higher than 50 A degrees C. The activator or inhibitor effects of ions such as Cu2+, Fe2+, Ca2+, Mg2+ and Zn2+ on activity of mannanase were also researched, and all metal ions except Ca2+ significantly affected enzyme activity in a positive direction. V (max) and K (m) values of mannanase for locust bean gum were 82.5 mg mannan/mL and 0.0178 mM. In addition, considering the biotechnological aspect, clarification of fruit juice was investigated. The purified enzyme was determined to be the most effective enzyme that can be used in clarifying the kiwi juice with a ratio of 117.21 %.