Understanding the Fatty Acids Removal from Bacterial Lipopolysaccharides via Enzymatically Activated Hydrolysis in Water

Abstract

Lipopolysaccharides (LPS) belongs to one of the strongest pathogens groups that can stimulate the human immune system. This molecule also known as endotoxin comes from the outer membrane of Gram-negative bacteria cell wall. Gram-negative bacteria shed-out LPS in the form of blebs from its outer membrane particularly after biofilms successfully mature in events where stagnated waters occur. Despite its pathophysiological toxicity mechanism are well- established, little is known about its interaction in water sources that ultimately reach people. LPS molecules are an important pathogen group that triggers a signal within the innate immune system. To occur the LPS agonist role in humans, it is necessary to stimulate the toll-like receptor 4 (TLR4) by using its six acyl chain from its lipid A moiety. The effect of this LPS triggered signal includes an initial strong inflammatory response by the immune system that subsequently is counteracted via the human enzyme acyloxyacyl hydrolase (AOAH). In nature, AOAH detoxifies LPS by removing fatty acids from lipid A component. The main purpose of this study is to mimic this biological response in-vitro by exploring a different enzyme in order to develop a sustainable water treatment technology. In this study we aim to explore a new detoxification mechanism to remove the fatty acids chains from the molecule using an enzymatic de-acylation procedure. The product of the de-acylation reaction had been characterized via gas chromatography (GC), free fatty acid assays (FFA), Fourier-transform infrared spectroscopy (FTIR), among others. Results have demonstrated viability of the reaction that will serve as the groundwork principle to develop further technology for water purification applications.The details for this investigation methods and analytical techniques will be presented.