Purification and characterisation of β‐mannanase from L actobacillus plantarum ( M 24) and its applications in some fruit juices

Summary β‐Mannanase was purified 2619.05‐fold from the Lactobacillus plantarum (M24) bacterium by ammonium sulphate precipitation and ion exchange chromatography (DEAE‐Sephadex). The purified enzyme gave two protein bands at a level of approximately 36.4 and 55.3 kDa in the SDS‐PAGE. The purified mannanase enzyme has shown its maximum activity at 50 °C and pH 8, and it has been also determined that the enzyme was stable at 5–11 pH range and over 50 °C. The Vmax and Km values have been identified as 82 mg mannan mL−1 and 0.178 mm, respectively. The effects of some metal ions such as Fe2+, Ca2+, Co2+, Ni2+, Mn2+, Cu2+ and Zn2+ on the mannanase enzyme have been also investigated, and it has been determined that all metal ions had significant effects on the activation of the mannanase enzyme. In addition, the effectiveness of the purified mannanase enzyme on the clarification of some fruit juices such as orange, apricot, grape and apple has been investigated. During the clarification processes, the enzyme was more effective than crude extracts on the clarification of the peach juice with a ratio of 223.1% at most.