Rapid screening for bacterial phenotypes capable of biodegrading anionic surfactants: development and validation of a microtitre plate method

Abstract

The Biolog microtitre plate assay, which is based on tetrazolium dye reduction as an indicator of sole-carbon-source utilization, has been evaluated as a rapid method to investigate the biodegradation of five classes of anionic surfactant by pure and mixed cultures of bacteria. The assay gave reproducible results over a fourfold range of inoculum optical density, and the surfactant concentration was selected t o provide a compromise between the length of the lag period prior to colour production and the maximum colour produced. A kinetic model was developed and used t o analyse the appearance of colour in the assay and was found t o give rise to three biologically significant parameters describing the processes underlying the assay. No false-positives were obtained with environmental isolates. The small number of falsenegatives obtained (< 8% of the total) could be explained by the methodology used to prepare the bacterial inoculum. All isolates which were positive in the Biolog assay were shown t o be both primary and ultimate degraders of the test surfactant. These results show that the method provides a useful means of studying the biodegradation of anionic surfactants by both pure and mixed cultures of bacteria and will find use in the rapid analysis of biodegradation kinetics and specificities of larger numbers of individual isolates than hitherto possible. In addition, an important benefit of the methodology is that it can be used for direct analysis of the biodegradation potential of whole bacterial communities without having t o make an artificial selection during laboratory growth.UK

Degradation of tannic acid by cold-adapted Klebsiella sp NACASA1 and phytotoxicity assessment of tannic acid and its degradation products

“…However, the pollution problem is often more serious at low temperatures (Lee et al 1995;Geerdink et al 1996;Marchesi et al 1997). Our isolate was able to degrade tannic acid efficiently at 15°C.…”

PAH biodegradation in surfactant‐water systems based on the theory of cohesive energy density (CED)

“…Carbon degradation potential (CDP) was calculated based on the following equation by Banerjee et al (1997):32 where A, B, C, D and E represent well numbers with a positive reaction in the Biolog GN microplate after 24 h, 36 h, 48 h, 60 h and 72 h incubation, respectively 33. Utilization of the Biolog carbon sources during PAH biodegradation was determined using the following equation: where N is the 95 wells addressed from A2 to H12 on the Biolog GN plate and 1 is the A1 well on the Biolog GN plate.…”

Phenotyping Microarrays for the Characterization of Environmental Microorganisms

“…For organisms, the following roots were used for the search: bacteria: bacter*, fungi:fung*, phytoplankton:phytopl*, protozoan:protozo*. Search for soil was with the roots soil*, sand*, clay*, rhizosphere; for aquatic with marine, lake*, river*, pond*, stream*, groundwater*; for human with human*, clinic* In addition to allowing the characterization of strains and communities based on their substrate metabolism or growth condition preferences and capacities, microtiter plate-based phenotype arrays can help establish intrinsic physiological trade-offs in microorganism [16] and help characterize metabolic pathways [17]. Furthermore, using Biolog™ plates could help discover ecotypes that can have specific biodegradation capacities, within microorganism species [18].…”

“…This process is repeated 3 times after which the cells are incubated in the impoverished medium or water. Cellular reserves naturally depend on cell type being assayed, but generally a 6-24 h starvation period applies to most microorganisms [17].…”