title: Starch industry wastewater for production of biopesticides--ramifications of solids concentrations.
abstract: Total solids (TS) concentrations ranging from 15 to 66 g L(-1) of starch industry wastewater (SIW) were tested as raw material for the production of Bacillus thuringiensis var. kurstaki HD-1 (Btk) biopesticide in shake flasks and a 15 L bench-scale fermenter. Shake flask studies revealed a higher delta-endotoxin concentration of Btk at 30 g L(-1) TS concentration and 2.5% (v v(-1)) volume of pre-culture. The fermenter experiments conducted using SIW at 30 g L(-1) TS concentration under controlled conditions of temperature, pH and dissolved oxygen showed higher spore count, enzyme production (protease and amylase) and delta-endotoxin concentration as compared with those of SIW at 15 g L(-1) TS concentration. The entomotoxicity, at the end of fermentation, with SIW at 30 g L(-1) solids concentration (17.8 x 10(9) SBU L(-1), measured against spruce budworm) was considerably higher as compared with entomotoxicity at 15 g L(-1) solids concentration (15.3 x 10(9) SBU L(-1)) and semi-synthetic medium (11.7 x 10(9) SBU L(-1)). The pellet, comprising spores and delta-endotoxin complex obtained after centrifugation and followed by resuspension (in supernatant) in one-tenth of the original volume, of SIW at 30 g L(-1) solids concentration media registered the highest potential for application (to protect forests against spruce budworm) than other media in term of entomotoxicity.
authors.affiliation: INRS-ETE, Université du Québec, 490 rue de la Couronne, Québec (Québec) G1K 9A9, Canada.
authors.forename: Khanh Dang
authors.initials: KD
authors.lastname: Vu
authors.forename: R D
authors.initials: RD
authors.lastname: Tyagi
authors.forename: S K
authors.initials: SK
authors.lastname: Brar
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; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D019149:Bioreactors; D015169:Colony Count, Microbial; D004731:Endotoxins / Q000378:metabolism*; D005285:Fermentation; D006460:Hemolysin Proteins / Q000378:metabolism*; D007220:Industrial Waste; D010572:Pest Control, Biological; D010575:Pesticides / Q000378:metabolism*; D013213:Starch; D013696:Temperature
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007220:Industrial Waste; D010575:Pesticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D013213:Starch