Alkaline lipase production by <i style="">Citrobacter freundii</i> IIT-BT L139

485-491Around 150 lipase producing bacterial isolates were screened from the local soils enriched with oil. Citrobacter freundii IIT-BT L139, an isolated microbial strain, produced lipase that had high activity (8.8 U/ml) at pH 9.0 and 40oC. The 16S rDNA phylogenetic studies showed that Citrobacter freundii belongs to the family Enterobacteriaceae and later confirmed by the microbial identification. Suitable C and N sources for lipase production were deduced to be starch and peptone-urea, respectively. In a controlled fermenter (1 L), the lipase activity was found to increase by 36% (12 Uml-1). The variation of lipase activity, pH and dissolved oxygen (DO) during growth of the organism in the controlled batch fermenter were monitored. The rheological characteristics of the fermentation broth indicated that it behaved like a Newtonian fluid throughout the fermentation. The fermentation time was comparatively short (60 h). The lipase was also found to be substantially resistant to common detergents. This lipase was, thus, characterized as alkaline, thermostable and solvent stable, which was essentially desirable in pharmaceutical, detergent and other industrial applications or production

Nutrients influence the dynamics of Klebsiella pneumoniae carbapenemase producing enterobacterales in transplanted hospital sinks

Antimicrobial resistance has been recognized as a threat to human health. The role of hospital sinks acting as a reservoir for some of the most concerning antibiotic resistant organisms, carbapenemase producing Enterobacterales (CPE) is evident but not well understood. Strategies to prevent establishment, interventions to eliminate these reservoirs and factors which drive persistence of CPE are not well established. We use a uniquely designed sink lab to transplant CPE colonized hospital sink plumbing with an aim to understand CPE dynamics in a controlled setting, notably exploiting both molecular and culture techniques. After ex situ installation the CPE population in the sink plumbing drop from previously detectable to undetectable levels. The addition of nutrients is followed by a quick rebound in CPE detection in the sinks after as many as 37 days. We did not however detect a significant shift in microbial community structure or the overall resistance gene carriage in longitudinal samples from a subset of these transplanted sinks using whole shotgun metagenomic sequencing. Comparing nutrient types in a benchtop culture study model, protein rich nutrients appear to be the most supportive for CPE growth and biofilm formation ability. The role of nutrients exposure is determining factor for maintaining a high bioburden of CPE in the sink drains and P-traps. Therefore, limiting nutrient disposal into sinks has reasonable potential with regard to decreasing the CPE wastewater burden, especially in hospitals seeking to control an environmental reservoir