Mosquito biolarvicide production by sequential fermentation with dual strains of Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus using sewage sludge.
This study demonstrated the bioconversion of sewage sludge into a composite biolarvicide for mosquito control based on sequential fermentation with dual strains of Bacillus thuringiensis subsp. israelensis (Bti) and Bacillus sphaericus (Bs). Results showed that sewage sludge was a suitable fermentation substrate for supporting growth, sporulation and mosquitocidal proteins synthesis by Bti and Bs. Through sequential fermentation with dual strains, a 10-L bench-scale fermentor was capable of producing Bti and Bs at a cell concentration of 2.1×10(9) and 6.8×10(8) CFU/mL, respectively. Such sequential fermentation can save half of raw materials and energy consumption comparing with the sludge fermentation with single strain. The toxic activity and persistence of the composite biolarvicide against mosquito larvae in the polluted waters were enhanced by the increased toxin complexity and synergistic interactions. This study, for the first time, validates the technical feasibility of using sewage sludge to produce a cost-effective composite biolarvicide based on Bti and Bs.
Zhuang
Li
L
Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
Zhou
Shungui
S
Wang
Yueqiang
Y
Chang
Min
M
D000330:Aedes / Q000187:drug effects / Q000254:growth & development; D000818:Animals; D001407:Bacillus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D019149:Bioreactors / Q000382:microbiology; D015169:Colony Count, Microbial; D003465:Culex / Q000187:drug effects / Q000254:growth & development; D009033:Culicidae / Q000187:drug effects* / Q000254:growth & development; D005285:Fermentation / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects*; D010572:Pest Control, Biological / Q000379:methods*; D012722:Sewage / Q000382:microbiology*; D013171:Spores, Bacterial / Q000187:drug effects / Q000502:physiology
D007306:Insecticides; D012722:Sewage