Chitinolytic functions in actinobacteria: ecology, enzymes, and evolution

Abstract

Actinobacteria, a large group of Gram-positive bacteria, secrete a wide range of extracellular enzymes involved in the degradation of organic compounds and biopolymers including the ubiquitous aminopolysaccharides chitin and chitosan. While chitinolytic enzymes are distributed in all kingdoms of life, actinobacteria are recognized as particularly good decomposers of chitinous material and several members of this taxon carry impressive sets of genes dedicated to chitin and chitosan degradation. Degradation of these polymers in actinobacteria is dependent on endo- and exo-acting hydrolases as well as lytic polysaccharide monooxygenases. Actinobacterial chitinases and chitosanases belong to nine major families of glycosyl hydrolases that share no sequence similarity. In this paper, the distribution of chitinolytic actinobacteria within different ecosystems is examined and their chitinolytic machinery is described and compared to those of other chitinolytic organisms.Electronic supplementary materialThe online version of this article (10.1007/s00253-018-9149-4) contains supplementary material, which is available to authorized users.

Enzymatic Degradation of <i>p</i>-Nitrophenyl Esters, Polyethylene Terephthalate, Cutin, and Suberin by Sub1, a Suberinase Encoded by the Plant Pathogen <i>Streptomyces scabies</i>

“…Other Streptomyces extracellular enzymes, e.g. chitosanases from the GH75 family, are encoded by genes that are also mainly represented in fungal and actinobacterial genomes (Lacombe-Harvey et al, 2018).…”

Feeding on fungi: genomic and proteomic analysis of the enzymatic machinery of bacteria decomposing fungal biomass

“…Yet, the rate and efficiency of chitin degradation appear to differ strongly among chitinolytic bacterial species (Bai et al ., 2016). The actinobacteria are supposed to be the most effective chitin degraders in the terrestrial ecosystem with an extensive set of chitinolytic enzymes (Lacombe‐Harvey et al ., 2018; Sun et al ., 2019). In general, most bacterial chitinases belong to monospecific family GH18, whereas the occurrence of chitinases belonging to the other monospecific chitinase family GH19 is less common (Nguyen et al ., 2018).…”

“…3). In detail, chitinolytic genes of Ewingella americana 193 resemble the system of chitinolytic actinobacteria, except for the lack of the lytic monooxygenase AA10 (Lacombe‐Harvey et al ., 2018; Sun et al ., 2019). Our other strains possessed a less complex set of chitinolytic genes, but as for Ewingella americana we detected genes for endo‐cleaving enzymes: endochitinase (CH18, CH19) and chitosanases (GH5 and GH8), exohydrolases: β‐N‐acetylglucosaminidase (GH3, GH5 and GH20) and β‐glucoseaminidase (GH2 and GH9).…”

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

“…By contrast, Granulicella had a negative correlation with groups of Actinobacteria, demonstrating a potential competition, where Actinobacteria are metabolizing WH15EPS and impacting negatively Granulicella. Actinobacteria are widely spread in the environment and play an essential role in carbon cycling, presenting a wide range of extracellular enzymes (Lacombe-Harvey et al, 2018). Furthermore, the presence of Granulicella in the heavy fraction demonstrates the capacity of the genus to use EPS as a carbon source; however, there is no experimental evidence that the producer strain is able to metabolize its own EPS.…”