Council of Scientific and Industrial Research

Department of Biotechnology

Madhusudana Rao Nalam

Lakshmi Prasanna Gangavaramu

Veerabhadrav Rao Arravapalli

Veerabhadra Rao Arravapalli

The present invention discloses a recombinant modified extracellular chitinase having an amino acid sequence set forth in SEQ ID NO. 4 or SEQ ID NO. 5 prepared by substituting two tyrosine (Y) residues with histidine (H) in the native chitinase ofLAK 1210. The modified chitinase represents an advancement as it has improved thermal stability, wider optimum pH range, high efficacy, improved solubility and low toxicity. The present invention also provides compositions and improved methods for producing and purifying the recombinant modified chitinase by chitin affinity chromatography and chitin adsorption affinity chromatography using shrimp shell and crab shell, for large scale production at low cost. The modified chitinase has wide range of applications including prevention, treatment or modulation of phytopathogenic infection in a plant or a plant part.

Recombinant extracellular chitinase fromfor biological control and other industrial uses

The present invention discloses a recombinant, modified extracellular chitinase having an amino acid sequence set forth in SEQ ID NO.4 or SEQ ID NO.5. The recombinant, modified chitinase is derived by inserting two-point mutations at positions 661 and 2158 in the native chitinase gene ofLAK 1210 which results in amino acid substitution of tyrosine (Y) residue with histidine (H) at positions 221 and 720. The modified chitinase exhibits both exochitinase and endochitinase activity. The recombinant, modified enzyme is thermoactive with a temperature optimum of 55-60&#xb0; C. and high thermostability (Tm of 66.7&#xb0; C.), functions in a broad pH range (pH 3.0-11.0) having a pH optimum of 9.0 and also exhibits improved solubility and enhanced efficacy for control of insects and phytopathogenic fungi. The invention further provides improved methods for large scale production of recombinant modified chitinase and rapid, cost-effective purification method by chitin-adsorption affinity chromatography using powdered crustacean shells.

Growing community of inventors

Telangana, India

Madhusudana Rao Nalam