Sludge based Bacillus thuringiensis biopesticides: viscosity impacts.
Viscosity studies were performed on raw, pre-treated (sterilised and thermal alkaline hydrolysed or both types of treatment) and Bacillus thuringiensis (Bt) fermented sludges at different solids concentration (10-40 g/L) for production of biopesticides. Correlations were established among rheological parameter (viscosity), solids (total and dissolved) concentration and entomotoxicity (Tx) of Bt fermented sludges. Exponential and power laws were preferentially followed by hydrolysed fermented compared to raw fermented sludge. Soluble chemical oxygen demand variation corroborated with increase in dissolved solids concentration on pre-treatments, contributing to changes in viscosity. Moreover, Tx was higher for hydrolysed fermented sludge in comparison to raw fermented sludge owing to increased availability of nutrients and lower viscosity that improved oxygen transfer. The shake flask results were reproducible in fermenter. This study will have major impact on selecting fermentation, harvesting and formulation techniques of Bt fermented sludges for biopesticide production.
INRS-Eau, Terre et Environnement (INRS-ETE), 2800 Rue Einstein, CP 7500, Sainte-Foy, Quebec, Canada G1V 4C7.
S K
SK
Brar
M
M
Verma
R D
RD
Tyagi
J R
JR
Valéro
R Y
RY
Surampalli
D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism*; D005285:Fermentation; D007814:Larva; D007915:Lepidoptera; D010572:Pest Control, Biological; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014783:Viscosity
D012722:Sewage