Exopolysaccharides directed embellishment of diatoms triggered on plastics and other marine litter

Abstract

In the present study, embellishment or beautification of diatoms on substrates like plastics, polydimethylsiloxane, graphite, glass plate, and titanium dioxide, triggered by exopolysaccharides was examined under laboratory conditions. Exopolysaccharides are secreted mainly by primary colonisers, bacteria, which is succeeded by secondary colonisers i.e. diatoms. Both diatom (Nitzschia sp.4) and bacteria (Bacillus subtilis) were exposed with substrates separately for 30 days. Diatoms adhere on substrates strongly, not only because of surface roughness of different substrates but also the nanoporous architecture of diatoms which enhanced their embellishment. This study attempted to identify the substrates that adhere to diatoms strongly and was mainly analyzed by scanning electron microscope and further the observations are well supported by math work software (MATLAB). The variation of diatom’s binding on different substrates is due to the influence of marine litters on diatom population in ocean beds where they undergo slow degradation releasing macro, micro and nanoparticles besides radicals and ions causing cell death. Therefore a proof-of-concept model is developed to successfully deliver a message concerning benefit of using different diatom species.

Design and Development of Fluorinated and Biocide-Free Sol–Gel Based Hybrid Functional Coatings for Anti-Biofouling/Foul-Release Activity

“…In particular, diatoms adhesion differs from bacteria one, not only because of surface roughness, but also for their nano-porous architecture that enhances their adhesion [ 74 ] on hydrophobic surfaces and fouling release coatings [ 75 ].…”

Epiplastic microhabitats for epibenthic organisms: a new inland water frontier for diatoms

“…According to Lagarde et al ( 2016 ), a solid surface of diverse materials placed in aquatic environment can be colonized by microorganisms such as bacteria, microalgae, and fungi. In marine environment, bacteria followed by microalgae resulted to be the first colonizers on plastic litter playing a key role and their colonization it is possible thanks to the production of exopolysaccharides, an extracellular polymeric substance (Khan et al 2020 ). However, there are very few studies on the colonization of plastics by diatoms in freshwaters that can be taken as a comparison, but there are some studies on the effects of microplastics on other microalgae taxa conducted in laboratory.…”

“…Anyway, it is evident that the diatom community colonizes plastic substrates regardless of the type of polymer in a relatively short time; therefore, we hypothesize that any plastic waste can be colonized by diatoms. It is important to highlight that a similar condition could be temporary because, according to Khan et al ( 2020 ), the litter sinking capability is enhanced by biofilms (exopolysaccharides) formed on their surfaces that increases the weight, so the floating supports could sink. Diatoms are important and abundant component of the biofilm biodiversity that colonizes the plastic in aquatic systems (Caruso 2020 ; Di Pippo et al 2020 ; Zhao et al 2021 ).…”

Plastic Interactions with Pollutants and Consequences to Aquatic Ecosystems: What We Know and What We Do Not Know

“…Dissolved organic matter (DOM) can physically interact with various chemical contaminants/pollutants and is also prone to being adsorbed onto the surface of plastic particles in fresh and marine waters. A major source of marine DOM comes from the exopolysaccharides (EPS) produced and released by phytoplankton (eukaryotic) and bacteria [ 142 ]. These EPS can interface with various low polarity chemicals.…”