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A bacterial population study of commercialized wastewater inoculants
Author(s) -
Vrints M.,
Bertrand S.,
Collard JM.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2007.03444.x
Subject(s) - bacteriology , library science , population , public health , medicine , biology , computer science , environmental health , genetics , nursing , bacteria
Aims: To assess the bacterial diversity and safety of wastewater inoculants, which are commercially available products used to improve the aerobic digestion processes of the domestic waste compost in the septic tank. Methods and Results: Eighteen wastewater inoculants were analysed on nonselective and selective media and the cultivable bacteria were identified. In all wastewater inoculants, the number of CFUs were between 10 4 and 10 7 g −1 powder on nonselective media and Bacillus was the predominant cultivable genus. Culture‐independent molecular methods such as sequencing of 16S rRNA clone libraries and denaturating gradient gel electrophoresis demonstrated the high prevalence of interfering chloroplast 16S rRNA from plant material and the presence of Bacillus spp. Only after selective enrichments and cultivation, the presence of one pathogenic strain ( Klebsiella pneumoniae subsp . pneumoniae ) and one opportunistic strain of ( Enterobacter cloacae) bacteria were detected in six different products. Conclusion: The predominant cultivable species of the wastewater inoculants were Bacillus spp. and after enrichment six products were found to contain opportunistic or pathogenic strains. Significance and Impact of the Study: The presence of opportunistic pathogenic strains in the inoculants might represent a risk for immunocompromised, the elderly or children. A clear labelling should therefore be displayed on the product.