title: [Bioconversion of sewage sludge to biopesticide by Bacillus thuringiensis].
abstract: Feasibility of bioconversion of sewage sludge to biopesticide by Bacillus thuringiensis was studied using sewage sludge as a raw material. The fermentation was also compared with conventional medium. Results showed that without any pretreatment, the nutrients contained in sewage sludge were almost sufficient for Bacillus thuringiensis growth, even with a rapid multiplicational rate. Higher viable cells and viable spores values were obtained earlier at 24 h, with 9.48 x 10(8) CFU x mL(-1) and 8.51 x 10(8) CFU x mL(-1) respectively, which was 12 hours earlier and nearly 20 percent higher than conventional medium. SEM of 36 h samples gave a clear phenomenon that the metabolizability in sludge was much faster with spores and crystals spreading around. The crystals in sludge seemed rather bigger and more regular. Also a better crystal protein yield of 2.80 mg x mL(-1) was observed in sludge medium compared to conventional medium at the end of fermentation. Sludge fermentation for Bacillus thuringiensis reduces the producing cost, and gives better fermentation capabilities. It's expected to be a new method for sludge disposal.
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Chang
authors.forename: Shun-gui
authors.initials: SG
authors.lastname: Zhou
authors.forename: Na
authors.initials: N
authors.lastname: Lu
authors.forename: Jin-ren
authors.initials: JR
authors.lastname: Ni
mesh_terms: D001413:Bacillus thuringiensis / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism; D015169:Colony Count, Microbial; D003470:Culture Media / Q000494:pharmacology; D004731:Endotoxins / Q000378:metabolism; D005285:Fermentation; D006460:Hemolysin Proteins / Q000378:metabolism; D007218:Industrial Microbiology / Q000295:instrumentation / Q000379:methods; D007306:Insecticides / Q000378:metabolism*; D050296:Microbial Viability; D012722:Sewage / Q000382:microbiology*; D013171:Spores, Bacterial / Q000187:drug effects / Q000502:physiology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D003470:Culture Media; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D012722:Sewage; C030956:insecticidal crystal protein, Bacillus Thuringiensis