title: Bacillus thuringiensis fermentation of hydrolyzed sludge--rheology and formulation studies.
abstract: Rheology of Bacillus thuringiensis fermentation of hydrolyzed sludge was investigated in bench scale fermenter. Stable liquid formulations were developed and optimized for two-year based studies comprising various physical/chemical (viscosity, particle size, corrosion and suspendibility) and biological (microbial contamination, viable spores and entomotoxicity) parameters at different pHs and temperatures. The hydrolyzed sludge depicted non-Newtonian and pseudoplastic behaviour during fermentation with 90% to 96% confidence of fits into Casson, Power and IPC paste models. Higher values of consistency and flow index during exponential growth and stationary phase, respectively, affected downstream processing. The power law was also followed by stable formulations. Sorbitol, sodium monophosphate and sodium metabisulfite (2.2:1:1) as suspending agents produced suspendibility ranging from 69% to 94%. The stable formulation (FH-4) comprising sorbitol, sodium monophosphate and sodium metabisulfite deteriorated at pHs 6, 6.5 and temperatures, 40 and 50 degrees C, with no signs of corrosion and microbial contamination. The viscosity of FH-4 formulations decreased with shear rate which could improve handling and consequent spraying.
authors.affiliation: INRS-ETE, Université du Québec, 490, de la Couronne, Québec, Canada G1K 9A9.
authors.forename: Satinder 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 / Q000254:growth & development* / Q000378:metabolism*; D005285:Fermentation / Q000502:physiology*; D006868:Hydrolysis; D010575:Pesticides / Q000378:metabolism; D012212:Rheology; D012722:Sewage; D033081:Shear Strength; D014783:Viscosity
chemical_list: D010575:Pesticides; D012722:Sewage