Isolation and identification of marine strains of Stenotrophomona maltophilia with high chitinolytic activity.

Roger Salas-Ovilla,Miguel Salvador-Figueroa,Didiana Gálvez-López,Alfredo Vázquez-Ovando,Raymundo Rosas-Quijano

doi:10.7717/peerj.6102

Abstract

Chitin is the second most abundant organic compound in nature and represents a rich carbon and nitrogen source that is primarily transformed by bacterial communities. Bacteria capable of gradually hydrolyzing chitin into N-acetylglucosamine monomers can have applications in the transformation of residues from shrimp and other crustaceans. The objective of the present study was to isolate, characterize and identify microorganisms with high chitinolytic activity. These microorganisms were isolated and characterized based on macro- and microscopic morphological traits. Strains were selected on colloidal chitin agar medium primarily based on a hydrolysis halo larger than 2 mm and a growing phase no longer than 6 days. Secondary selection consisted of semi-quantitative evaluation of chitinolytic activity with a drop dilution assay. From the above, ten strains were selected. Then, strain-specific activity was evaluated. The B4 strain showed the highest specific activity, which was 6,677.07 U/mg protein. Molecular identification indicated that the isolated strains belong to the species Stenotrophomonas maltophilia.

Highlights

Shrimp production in Latin America was estimated to be between 500,000 and 600,000 tons in 2016, with Mexico being one of the main suppliers (FAO, 2016)
The strains B2, B3, B5, B8, B9 and B10 were isolated from shrimp shells, and the strains B1, B4, B6 and B7 were isolated from seawater
These results indicated that the 10 selected strains have different capacities to hydrolyze chitin

Summary

Introduction

Shrimp production in Latin America was estimated to be between 500,000 and 600,000 tons in 2016, with Mexico being one of the main suppliers (FAO, 2016). The commercialization of this crustacean generated an economic revenue of more than 16 million pesos in 2016, the residues generated by the shrimp industry have a negative impact on the environment (SIAP, 2016). Of these residues, approximately 5% is transformed into products such as flours and extracts, which serve as a base for animal feed (Laxman et al, 2016). There are two pathways for the production of chitin oligosaccharides: the chemical pathway and the biotechnological pathway. The biotechnological pathway is an environmentally friendly process

Objectives

Methods

Results

Discussion

Conclusion