Bacterial Degradation of Algal Polysaccharides in Marine Ecosystem

Imran, Imran; Poduval, Preethi B.; Ghadi, Sanjeev C.

doi:10.1007/978-981-10-1044-6_12

Cited by 12 publications

(10 citation statements)

References 95 publications

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“…This alternation on the one hand allowed quick purification of desired methanotrophs from non-methanotrophic bacteria which can feed on methanotrophic metabolites such as acetate, formate and lactate (Whittenbury et al 1970 ). On the other hand, some non-methanotrophs can grow on polysaccharides which make up agar, therefore switching from agar to liquid media potentially eliminated these contaminants (Payton and Roberts 1976 ; Imran et al 2016 ). Furthermore, extinction dilution culturing was employed when transferring to liquid medium which further benefitted purification (Hoefman et al 2012 ).…”

Section: Discussionmentioning

confidence: 99%

Isolation and characterisation of Methylocystis spp. for poly-3-hydroxybutyrate production using waste methane feedstocks

et al. 2021

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Waste plastic and methane emissions are two anthropogenic by-products exacerbating environmental pollution. Methane-oxidizing bacteria (methanotrophs) hold the key to solving these problems simultaneously by utilising otherwise wasted methane gas as carbon source and accumulating the carbon as poly-3-hydroxybutyrate, a biodegradable plastic polymer. Here we present the isolation and characterisation of two novel Methylocystis strains with the ability to produce up to 55.7 ± 1.9% poly-3-hydroxybutyrate of cell dry weight when grown on methane from different waste sources such as landfill and anaerobic digester gas. Methylocystis rosea BRCS1 isolated from a recreational lake and Methylocystis parvus BRCS2 isolated from a bog were whole genome sequenced using PacBio and Illumina genome sequencing technologies. In addition to potassium nitrate, these strains were also shown to grow on ammonium chloride, glutamine and ornithine as nitrogen source. Growth of Methylocystis parvus BRCS2 on Nitrate Mineral Salt (NMS) media with 0.1% methanol vapor as carbon source was demonstrated. The genetic tractability by conjugation was also determined with conjugation efficiencies up to 2.8 × 10–2 and 1.8 × 10–2 for Methylocystis rosea BRCS1 and Methylocystis parvus BRCS2 respectively using a plasmid with ColE1 origin of replication. Finally, we show that Methylocystis species can produce considerable amounts of poly-3-hydroxybutyrate on waste methane sources without impaired growth, a proof of concept which opens doors to their use in integrated bio-facilities like landfills and anaerobic digesters.

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Section: Discussionmentioning

confidence: 99%

Isolation and characterisation of Methylocystis spp. for poly-3-hydroxybutyrate production using waste methane feedstocks

et al. 2021

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“…Generally, polysaccharides are the main component of macroalgal cell walls (Imran et al 2017). These polysaccharides are the substrate for various polysaccharide-degrading enzymes produced by agarolytic bacteria, which utilize polysaccharides as a carbon and energy source and facilitate the biogeochemical cycle.…”

Section: Discussionmentioning

confidence: 99%

“…These polysaccharides are the substrate for various polysaccharide-degrading enzymes produced by agarolytic bacteria, which utilize polysaccharides as a carbon and energy source and facilitate the biogeochemical cycle. Notwithstanding, polysaccharides play an important role in protecting the host from pathogens and predators (Imran et al 2017). Therefore, the presence of agardegrading bacteria Marinagarivorans sp.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the possible deleterious impact of grazing on the algal host, the grazed G. firma can potentially be utilized as a bioresource for production of agar-derived biofuel due to its readily available reservoir of agarolytic bacteria (Kwak et al 2012). Moreover, polysaccharide-degrading bacteria isolated from grazed G. firma can potentially be applied in the degradation of algal waste (Satomi and Fujii 2014;Imran et al 2017).…”

Section: Discussionmentioning

confidence: 99%

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The effect of grazing on the microbiome of two commercially important agarophytes, Gracilaria firma and G. salicornia (Gracilariaceae, Rhodophyta)

et al. 2020

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Grazing, which leads to losses in biomass and drastic declines in total crop production, is one of the main concerns in seaweed aquaculture. This is also thought to affect the composition of the associated bacterial communities which are believed to play a crucial role in determining the host's health and development. Apart from morphological impairment, studying changes in the prokaryotic microbiome composition and predicted functional responses to grazing will allow us to understand the underlying effects of grazing on the seaweed host. This study is the first report of the effect of grazing on the prokaryotic microbiome of two economically important agarophytes, Gracilaria firma and Gracilaria salicornia, by high-throughput sequencing targeting the V3-V4 variable region of the 16S rRNA gene. The results indicated that for G. firma, the microbiome composition of tissues grazed by marine herbivores had significantly more agarolytic bacteria Marinagarivorans sp. and Algisphaera sp. than in ungrazed tissues. The predictive functional metagenomics for this species revealed that grazing escalated the pathway activities related to nucleotide degradation, aromatic compound degradation and aerobic sugar metabolism, while pathways associated with cell wall synthesis, aerobic respiration, vitamin biosynthesis and amino acid biosynthesis were reduced. However, for G. salicornia, the bacterial communities were not significantly affected by grazing. Nevertheless, pathways relating to anaerobic respiration and amino acid, coenzyme and vitamin B-6 biosynthesis in this species were predicted to be more active in grazed tissues, whereas the microbiome of ungrazed tissues had higher activities in bacteriochlorophyll a, fatty acid, secondary metabolite and heme biosynthesis.

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“…Polysaccharide-degrading bacteria are important members of the macroalgal bacterial community: by using algal cell wall polymers as carbon source, they contribute to the global carbon cycle (Gupta et al 2013 ) and, broadly, to macroalgal holobiont maintenance (Martin et al 2015 ). Some bacterial species can play a crucial role when macroalgal degradation processes occur, allowing the decay of macroalgae with consequent carbon compound recycling in the marine environment (Imran et al 2017 ). It is therefore of particular interest to focus attention on the specific microbial community that dominates the surface of decaying, besides than healthy, macroalgae (Ihua et al 2019 ).…”

Section: Introductionmentioning

confidence: 99%

What lies on macroalgal surface: diversity of polysaccharide degraders in culturable epiphytic bacteria

et al. 2022

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Macroalgal surface constitutes a peculiar ecological niche and an advantageous substratum for microorganisms able to degrade the wide diversity of algal glycans. The degrading enzymatic activities of macroalgal epiphytes are of paramount interest for the industrial by-product sector and biomass resource applications. We characterized the polysaccharide hydrolytic profile of bacterial isolates obtained from three macroalgal species: the red macroalgae Asparagopsis taxiformis and Sphaerococcus coronopifolius (Rhodophyceae) and the brown Halopteris scoparia (Phaeophyceae), sampled in South Portugal. Bacterial enrichment cultures supplemented with chlorinated aliphatic compounds, typically released by marine algae, were established using as inoculum the decaying biomass of the three macroalgae, obtaining a collection of 634 bacterial strains. Although collected from the same site and exposed to the same seawater seeding microbiota, macroalgal cultivable bacterial communities in terms of functional and phylogenetic diversity showed host specificity. Isolates were tested for the hydrolysis of starch, pectin, alginate and agar, exhibiting a different hydrolytic potential according to their host: A. taxiformis showed the highest percentage of active isolates (91%), followed by S. coronopifolius (54%) and H. scoparia (46%). Only 30% of the isolates were able to degrade starch, while the other polymers were degraded by 55–58% of the isolates. Interestingly, several isolates showed promiscuous capacities to hydrolyze more than one polysaccharide. The isolate functional fingerprint was statistically correlated to bacterial phylogeny, host species and enrichment medium. In conclusion, this work depicts macroalgae as holobionts with an associated microbiota of interest for blue biotechnologies, suggesting isolation strategies and bacterial targets for polysaccharidases’ discovery.

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Bacterial Degradation of Algal Polysaccharides in Marine Ecosystem

Cited by 12 publications

References 95 publications

Isolation and characterisation of Methylocystis spp. for poly-3-hydroxybutyrate production using waste methane feedstocks

Isolation and characterisation of Methylocystis spp. for poly-3-hydroxybutyrate production using waste methane feedstocks

The effect of grazing on the microbiome of two commercially important agarophytes, Gracilaria firma and G. salicornia (Gracilariaceae, Rhodophyta)

What lies on macroalgal surface: diversity of polysaccharide degraders in culturable epiphytic bacteria

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