Characterization of novel Acidobacteria exopolysaccharides with potential industrial and ecological applications

Abstract

Acidobacteria have been described as one of the most abundant and ubiquitous bacterial phyla in soil. However, factors contributing to this ecological success are not well elucidated mainly due to difficulties in bacterial isolation. Acidobacteria may be able to survive for long periods in soil due to protection provided by secreted extracellular polymeric substances that include exopolysaccharides (EPSs). Here we present the first study to characterize EPSs derived from two strains of Acidobacteria from subdivision 1 belonging to Granulicella sp. EPS are unique heteropolysaccharides containing mannose, glucose, galactose and xylose as major components, and are modified with carboxyl and methoxyl functional groups that we characterized by Fourier transform infrared (FTIR) spectroscopy. Both EPS compounds we identified can efficiently emulsify various oils (sunflower seed, diesel, and liquid paraffin) and hydrocarbons (toluene and hexane). Moreover, the emulsions are more thermostable over time than those of commercialized xanthan. Acidobacterial EPS can now be explored as a source of biopolymers that may be attractive and valuable for industrial applications due to their natural origin, sustainability, biodegradability and low toxicity.

Deciphering bacterial community variation during soil and leaf treatments with biologicals and biofertilizers to control huanglongbing in citrus trees

“…Using metagenomic and metatranscriptomic approaches, Bradyrhizobium was found to be related to HLB (Zhang et al, ), which supports the results of the current study. Norank_f__Acidobacteriaceae__Subgroup_1_ has been reported as a plant growth‐promoting bacteria (Kielak et al, ; Kielak, Cipriano, & Kuramae, ). Thus, it is clear that the treatments promoted the growth of beneficial bacteria.…”

Responses of Acidobacteria Granulicella sp. WH15 to High Carbon Revealed by Integrated Omics Analyses

“…The saccharide gene clusters revealed by ANTISMASH analysis are likely involved in the production of capsule, antigen, and exopolymers. Exopolymer production by this strain has been observed under laboratory conditions, and the composition of the biopolymer has been characterized [42]. Members of the phylum Acidobacteria are generally considered slow-growing organisms that succeed in oligotrophic environments.…”

Dynamics of active potential bacterial and fungal interactions in the assimilation of acidobacterial EPS in soil

“…Acidobacteria such as strains Ellin6076 and Ellin345 (Ward et al, 2009), Terriglobus tenax (Whang et al, 2014) and Granulicella sp. strains WH15 and 5B5 (Kielak et al, 2017) produce extracellular polymeric substances (EPS). EPS are biopolymers secreted by a variety of microorganisms and mainly comprise carbohydrates, proteins and DNA.…”

“…EPS may positively impact bacterial survival and function by enhancing bacterial quorum sensing, thus stimulating important metabolic activities and consequently promoting syntrophic interactions (Wingender et al, 1999). EPS production has been implicated in the long-term survival of Acidobacteria in several environments due to its protective properties (Kielak et al, 2017). Among Acidobacteria, EPS have only been isolated and chemically characterized from Granulicella sp.…”

“…Among Acidobacteria, EPS have only been isolated and chemically characterized from Granulicella sp. strains WH15 and 5B5, and the emulsion capacity of these EPS suggests potential industrial and environmental bioremediation applications (Kielak et al, 2017). EPS also serve as nutrient sources for other microorganisms (Flemming and Wingender, 2010), and the use of EPS from microbes other than Acidobacteria as a nutrient has been investigated in cross-feeding experiments.…”