Microbial mats in French Polynesia and their biotechnological applications

Abstract

a b s t r a c tIt is well known that microorganisms well-adapted to survival in extreme ecosystems could be considered as new sources of biomolecules that have biotechnological importance. On French Polynesian atolls, microbial mats are developing in water ponds exposed to fluctuations in physical and chemical parameters. In these microbial mats, which are called "kopara" by the inhabitants, bacteria coexist with cyanobacteria, and a synergistic relationship may exist between these two types of living microorganisms. A large number of cyanobacteria and bacteria have been isolated from different mats. Under laboratory conditions, these microorganisms were shown to produce various exopolymers, including exopolysaccharides and poly-␤-hydroxyalkanoates, along with pigments for further commercial developments. This manuscript gives an overview of substances isolated and characterized from these bacteria and cyanobacteria and discusses their potential applications in biotechnology.

Patterns of metal distribution in hypersaline microbialites during early diagenesis: Implications for the fossil record

“…In this zone, FeS reacts with sulfide‐forming FeS 2 , following the reaction FeS + H 2 S = FeS 2 + H 2 (Schoonen, ), and a higher metal content per volume microbialite is present. In addition to the physicochemical changes with depth, the organic matrix is progressively degraded by heterotrophic processes (Braissant et al., ; Guezennec et al., ; Wieland et al., ). This is confirmed by CLSM images showing likely degraded EPS near the bottom of the core as well as by the decrease in EPS with depth (Figure ; TS2).…”

Partial characterization of an exopolysaccharide secreted by a marine bacterium,Vibrio neocaledonicussp. nov., from New Caledonia

“…; Guezennec et al . ). Hexosamines predominated with concentrations up to 40·5%, while uronic acids and neutral sugars accounted for 10 and 5% of the total sugars, respectively.…”

“…Similar high uptake capacities were found for hexosamine‐rich exopolysaccharide produced by a marine bacterium isolated from a microbial mat in a Polynesian atoll with 400 mg Cu(II) g −1 EPS and 65 mg Ni(II) g −1 EPS, respectively (Guezennec et al . ). Further structural elucidation will allow a better understanding of the mechanism of this affinity and also determine the potential commercial value of this EPS as a biosorbent for a variety of heavy metals.…”

“…In that Pacific Ocean seems to be a promising source of new bacterial molecules and other marine biotechnological developments, such as novel drugs and healthcare products (Guezennec et al . ). A similar programme started in New Caledonia in April 2010 with the aim to isolate marine bacteria and evaluate their biotechnological potential.…”

Isolation and partial characterization of bacteria (Pseudoalteromonas sp.) with potential antibacterial activity from a marine costal environment from New Caledonia

“…For that purpose, a bioprospection started a few years ago on microbial mats of some French Polynesian atolls where micro‐organisms are exposed to high variation of abiotic factors (Guezennec et al . ) and in New Caledonia, which is known for its high endemic biodiversity and a large variety of marine costal environments (Chalkiadakis et al . ).…”