Screening for chitinolytic activity in the bacterial strains from different Pacific Ocean regions revealed that the highly active representatives belong to the genera Microbulbifer, Vibrio, Aquimarina, and Pseudoalteromonas. The widely distributed chitinolytic species was Microbulbifer isolated from the sea urchin Strongylocentrotus intermedius. Among seventeen isolates with confirmed chitinolytic activity, only the type strain P. flavipulchra KMM 3630^T and the strains of putatively new species Pseudoalteromonas sp. B530 and Vibrio sp. Sgm 5, isolated from sea water (Vietnam mollusc farm) and the sea urchin S. intermedius (Peter the Great Gulf, the Sea of Japan), significantly suppressed the hyphal growth of Aspergillus niger that is perspective for the biocontrol agents’ development. The results on chitinolytic activities and whole-genome sequencing of the strains under study, including agarolytic type strain Z. galactanivorans Dji^T, found the new functionally active chitinase structures and biotechnological potential.

Advances in the computational annotation of genomes and the predictive potential of current metabolic models, based on more than thousands of experimental phenotypes, allow them to be applied to identify the diversity of metabolic pathways at the level of ecophysiology differentiation within taxa and to predict phenotypes, secondary metabolites, host-associated interactions, survivability, and biochemical productivity under proposed environmental conditions. The significantly distinctive phenotypes of members of the marine bacterial species Pseudoalteromonas distincta and an inability to use common molecular markers make their identification within the genus Pseudoalteromonas and prediction of their biotechnology potential impossible without genome-scale analysis and metabolic reconstruction. A new strain, KMM 6257, of a carotenoid-like phenotype, isolated from a deep-habituating starfish, emended the description of P. distincta, particularly in the temperature growth range from 4 to 37 °C. The taxonomic status of all available closely related species was elucidated by phylogenomics. P. distincta possesses putative methylerythritol phosphate pathway II and 4,4′-diapolycopenedioate biosynthesis, related to C30 carotenoids, and their functional analogues, aryl polyene biosynthetic gene clusters (BGC). However, the yellow-orange pigmentation phenotypes in some strains coincide with the presence of a hybrid BGC encoding for aryl polyene esterified with resorcinol. The alginate degradation and glycosylated immunosuppressant production, similar to brasilicardin, streptorubin, and nucleocidines, are the common predicted features. Starch, agar, carrageenan, xylose, lignin-derived compound degradation, polysaccharide, folate, and cobalamin biosynthesis are all strain-specific.

The highly chitinolytic marine bacterium Vibrio jasicida KMM 6832, which exhibits potent antifungal activity, possesses an atypical Glycosyl Hydrolase family 19 (GH19) chitinase (ChitVjs). This is the first report of a GH19 gene in V. jasicida, an enzyme generally absent in this species and rare within the Harveyi clade. Phylogenetically, ChitVjs-like enzymes from the genera Vibrio and Aeromonas form a distinct cluster, separate from typical plant and bacterial GH19 counterparts. Despite high sequence identity (80–94%) with characterized homologs from V. parahaemolyticus and V. cholerae, ChitVjs is distinguished by its obligate halophilicity (optimum 0.3–0.4 M NaCl), an acidic isoelectric point (pI 4.72), and a broader cation-activation profile (K⁺, Ni²⁺, Ca²⁺, Cu²⁺, Co²⁺). The recombinant ChitVjs was produced in E. coli as a soluble 63 kDa protein. It functions as a stable, salt-dependent endo-chitinase/chitosanase, exhibiting optimal activity at 40 °C and pH 7.0. The enzyme displays high affinity for colloidal chitin (K_M 0.377 mg·mL⁻¹), is activated by DTT and Tween 80, and shows moderate stability in organic solvents. Furthermore, unlike its primarily catabolic relatives, ChitVjs suppresses conidial germination in marine-derived Aspergillus strains. These findings suggest that ChitVjs significantly contributes to the competitive fitness of V. jasicida KMM 6832 in high-salinity marine environments through both nutrient acquisition and antagonism.