Control of biofouling by xanthine oxidase on seawater reverse osmosis membranes from a desalination plant: enzyme production and screening of bacterial isolates from the full-scale plant

Abstract

Significance and Impact of the studyXanthine oxidase, an oxidoreductase enzyme that generates reactive oxygen species, is endogenously produced by many bacterial species. In this study, production of the enzyme by bacterial isolates from a full-scale desalination plant, was investigated for potential use as biological control of membrane fouling in seawater desalination. We have previously demonstrated that free radicals generated by a commercially available xanthine oxidase in Accepted ArticleThis article is protected by copyright. All rights reserved.the presence of a hypoxanthine substrate, effectively dispersed biofilm polysaccharides on industrially fouled membranes. Bacterial xanthine oxidase production in the presence of hypoxanthine may prove to be a cost effective, in situ method for alleviation of fouling. AbstractControl of biofouling on seawater reverse osmosis (SWRO) membranes is a major challenge as treatments can be expensive, damage the membrane material and often biocides do not remove the polymers in which bacteria are embedded. Biological control has been largely ignored for biofouling control. The objective of this study was to demonstrate the effectiveness of xanthine oxidase enzyme against complex fouling communities and then identify naturally occurring bacterial strains that produce the free radical generating enzyme. Initially, 64 bacterial strains were isolated from different locations of the Perth Seawater Desalination Plant. In our preceding study, 25/64 isolates were selected from the culture collection as models for biofouling studies, based on their prevalence in comparison to the genomic bacterial community. In this study, screening of these model strains was performed using a nitroblue tetrazolium assay in the presence of hypoxanthine as substrate.Enzyme activity was measured by absorbance. Nine of 25 strains tested positive for xanthine oxidase production, of which Exiguobacterium from sand filters and Microbacterium from RO membranes exhibited significant levels of enzyme production. Other genera that produced xanthine oxidase were Marinomonas, Pseudomonas, Bacillus, Pseudoalteromonas and Staphylococcus. Strain variations were observed between members of genera Microbacterium and Bacillus.

Bioprospecting and Exploration of the Natural Antifouling Approaches against Marine Foulers

“…Therefore, it is essential and expanding quickly to produce ecologically friendly coatings (Figure 7). 69,70 Lichens are major components of earthbound and marine environments. 72 Since lichen-associated bacteria make up a crucial part of lichen thalli, the conventional understanding of lichens should be widened to take bacteria into account.…”

Draft Genome Sequences of Three Bacillus Species Isolated from Biofouled Reverse-Osmosis Membranes

“…The bacilli in seawater can initiate biofouling of reverse-osmosis (RO) membranes ( 2 ), which leads to increased maintenance and water treatment costs. In addition, bacilli have been shown to produce xanthine oxidase, a free radical-generating enzyme that can be implemented in biological control of fouling ( 3 ). Therefore, these bacteria provide a valuable resource for studies on the formation of biofouling and its control.…”

Evaluation of Enzymatic Cleaning on Food Processing Installations and Food Products Bacterial Microflora

“…However, studies evaluating the efficacy of enzyme-based detergents have been conducted in labs or pilot plant scale models (Oulahal et al, 2007;Lequette et al, 2010;Lefebvre et al, 2016;Stiefel et al, 2016;Nagaraj et al, 2017). Lab models have their own advantages and their own limitations, but they could never mimic the real conditions that can be encountered in industries.…”