title: Bacillus thuringiensis fermentation of wastewater and wastewater sludge--presence and characterization of chitinases.
abstract: This study investigated the presence of chitinases in Bacillus thuringiensis ssp kurstaki HD-1 (Bt) fermented broths of wastewater sludge (non-hydrolyzed and hydrolyzed); starch industry wastewater and soyameal. Chitinase activity was absent in soyameal and present in others. Chitinase demonstrated peaks at pH 4.0 and temperatures 40 and 50 degrees C with higher activity between pH 4-5 and 10-11. The chitinase band on SDS-PAGE was found to be between 36 and 45 kDa for non-hydrolyzed (NH) and hydrolyzed sludge (TH) and starch industry wastewater. The chitinase profile during fermentation showed peaks at 15 and 30 h for non-hydrolyzed and hydrolyzed sludge and 15 and 24 h for starch industry wastewater. Chitinase retained 96-99 % activity after two weeks incubation at room temperature and pH 4. Bioassays with supplementation of Bt chitinases showed 1.2 fold increase in entomotoxicity of wastewater sludge and a small increase in starch industry wastewater. This study sheds light on production of Bt chitinases in alternative media which will have a long term effect on entomotoxicity of these formulations.
authors.affiliation: INRS Eau, Terre et Environnement (INRS-ETE), 490, de la Couronne, CP 7500, Québec, Canada G1K 9A9.
authors.forename: S K
authors.initials: SK
authors.lastname: Brar
authors.forename: M
authors.initials: M
authors.lastname: Verma
authors.forename: R D
authors.initials: RD
authors.lastname: Tyagi
authors.forename: J R
authors.initials: JR
authors.lastname: Valéro
authors.forename: R Y
authors.initials: RY
authors.lastname: Surampalli
mesh_terms: D001413:Bacillus thuringiensis / Q000378:metabolism*; D001681:Biological Assay; D002627:Chemistry, Physical / Q000379:methods; D002688:Chitinases / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008970:Molecular Weight; D012722:Sewage / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D002688:Chitinases