Denitrification with ɛ-caprolactam by acclimated mixed culture and by pure culture of bacteria isolated from polyacrylonitrile fibre manufactured wastewater treatment system

Abstract

The aim of this study is to isolate denitrifying bacteria utilizing epsilon-caprolactam as the substrate, from a polyacrylonitrile fibre manufactured wastewater treatment system. The aim is also to compare the performance of PAN (polyacrylonitrile) mixed bacteria cultures acclimated to epsilon-caprolactam and isolated pure strain for treating different initial epsilon-caprolactam concentrations from synthetic wastewater under anoxic conditions. The result showed that the PAN mixed bacteria cultures acclimated to epsilon-caprolactam could utilize 1538.5 mg/l of epsilon-caprolactam as a substrate for denitrification. Sufficient time and about 2200 mg/l of nitrate were necessary for the complete epsilon-caprolactam removal. Paracoccus thiophilus was isolated from the polyacrylonitrile fibre manufactured wastewater treatment system and it could utilize 1722.5 mg/l of epsilon-caprolactam as a substrate for denitrification. About 3500 mg/l of nitrate was necessary for the complete removal of epsilon-caprolactam. When the initial epsilon-caprolactam concentration was below 784.3 mg/l, the removal efficiency of epsilon-caprolactam by Paracoccus thiophilus was better than that for the PAN mixed bacteria cultures. The growth of Paracoccus thiophilus was better. However, when the initial epsilon-caprolactam concentration was as high as 1445.8 mg/l, both the epsilon-caprolactam removal efficiency by Paracoccus thiophilus and Paracoccus thiophilus specific growth rate were similar to the PAN mixed bacteria cultures.

Biodegradation of propionitrile by Klebsiella oxytoca immobilized in alginate and cellulose triacetate gel

“…[9], Rhodococcus equi A4 [10], Rhodococcus erythropolis A10 [11], C. guilliermondii UFMG-Y65 [12], Cryptococcus sp. UFMG-Y28 [13], Brevibacterium imperalis CBS489-74 [14], Rhodococcus rhodochrous LL100-21 [15], Pseudomonas stutzeri [16], Paracoccus thiophilus [17], Kluyveromyces thermotolerans MGBY 37 [18], and Candida guilliermondii CCT 7202 [19]. Microbial biotransformation of nitriles proceeds by two distinct routes; the one-step reaction catalyzed by nitrilase (EC 3.5.5.1) transforms nitriles directly into acids, or the two-step reaction catalyzed by nitrile hydratase (EC 4.2.1.84; NHase) forms amide, which is further hydrolysed to the acid with the release of ammonia by an amidase (EC 3.5.1.4) [18][19][20].…”

ε-Caprolactam Utilization by Proteus sp. and Bordetella sp. Isolated From Solid Waste Dumpsites in Lagos State, Nigeria, First Report

“…2). All these bacterial groups have been reported in studies involving solid waste dumpsites [9][10][11][12] except isolate identified as Proteus sp. (strain NTS2).…”

Enrichment, isolation, and characterization of 4-chlorophenol-degrading bacterium Rhizobium sp. 4-CP-20

“…Optimum temperature for growth experiment The optimum temperature for the growth of the bacterial isolates was determined following the procedure of Lee and Wang (2004) but using 350 mg l À1 of glucose or sodium acetate as the growth substrate under aerobic condition. Optical density at 600 nm was followed as a measurement of growth, and the mid-log growth data for strain was selected for calculating the specific growth rates.…”