Complete mineralization of dodecyldimethylamine using a two‐membered bacterial culture

Abstract

Complete degradation of dodecyldimethylamine was achieved using a two-membered bacterial culture isolated from activated sludge. One member, identified as Burkholderia cepacia, was capable of degrading the alkyl chain of the molecule. The other member, identified as Stenotrophomonas maltophilia, was able to degrade dimethylamine, the product of the former. Batch culture experiments revealed that the two-membered culture consisting of B. cepacia and S. maltophilia was based on a commensalistic relationship under carbon-limited conditions. Under nitrogen-limited conditions, the relationship of this culture was transformed from a commensalistic to a mutualistic one. A two-membered culture was therefore imperative for growth on dodecyldimethylamine under nitrogen-limited conditions, whereas a pure culture of B. cepacia was capable of growth on dodecyldimethylamine under carbon-limited conditions.

Synthetic cooperation in engineered yeast populations

“…6]. Together, R 3 L 4A and Y 3 A 4L form a cooperative system termed CoSMO (cooperation that is synthetic and mutually obligatory), which mimics two-species obligate mutualistic systems in which cooperation is essential for the survival of both species (11,14,17,19,27,28).…”

“…In fact, each population is essentially only one mutation step away from being a cooperator. Despite its artificial origin, CoSMO closely mimics aspects of naturally occurring cooperative systems such as exchange of essential nutrients between partners (14,19,28), death of a fraction of one partner population to support the reproduction of the other partner (11,27), and delayed reward for a particular investment (11,27). Even with obstacles such as severe delays in nutrient release, significant asymmetry in partners' starvation tolerance, and skewed population ratios resulting from intrinsic dynamics, the range of conditions permissible for cooperation is wide, consistent with the diversity observed in naturally occurring cooperative systems (2,3).…”

Biodegradation of p-toluenesulphonamide by a Pseudomonas sp.

“…The non-purgeable organic carbon (NPOC) contents were determined using a TOC analyser [8]. Ammonia was determined colourimetrically [8].…”

“…Cultures were grown in the sterilised mineral salts medium with 1 g l 31 of the respective carbon sources as described previously [8]. When methylcatechol and 3,4-dihydroxybenzoic acid were used as carbon source, these chemicals were sterilised separately by ¢ltration.…”

“…The speci¢c growth rate was estimated as described previously [8]. The culture was shaken at 200 rpm in an orbital incubator at 30³C.…”