Unraveling the Bacterial Assisted Degradation Pathway of Morpholine- a Xenobiotic Micropollutant: A Sustainability for Zero Pollution Environment

Abstract

Biodegradation is the process by which chemicals both natural and xenobiotics are metabolized by microorganisms. Most naturally occurring chemical compounds are biodegradable while xenobiotic may be biodegradable, persistent or recalcitrant. Xenobiotic chemicals, because they are manmade and have developed recently, are present in the environment for comparatively shorter periods of time from its geological presence. This in turn means that the microbial communities present in these environments may not have evolved specific mechanisms for their degradation. Morpholine, a known xenobiotics micropollutant initially believes to be recalcitrant but later prove to be biodegradable by specific set of bacterium species most likely Mycobacterium and Pseudomonas sp in particular. However, the metabolic pathways involved in the successful biodegradation of morpholine stand challenging to establish because of its extreme water solubility and the lack of any chromophore group in morpholine which does not allow easy extraction process. Consequently, no tool for direct estimation of intermediates or metabolites of morpholine has been well reported and only indirect strategies have been developed like presence of microbial growth on intermediates, chemical/analytical assay for intermediate and ammonia measurements to elucidate the degradation pathway for zero pollution environment. In this present study degradation pathway has been ascertained by some selected bacterial isolate for their capacity to degrade morpholine. Based on the said analysis of culture filtrate, it has been revealed that the isolate namely Halobacillus utilizes glycolic route of the metabolic degradation pathway of morpholine and supports the fact that in presence of morpholine, one of two branches of morpholine biodegradation pathway namely ethanolamine and glycolate was was induced while the other branch was inhibited. Whatever the degradation pathway of morpholine exhibited by bacteria, ammonia is the end product of degradation which would be biochemically utilized by isolate.