A new strain of T22.7.1 and its functional potential for deacetylation of chitin and chitooligsaccharides.

Introduction: Chitin, abundant in marine environments, presents significant challenges in terms of transformation and utilization. A strain, T22.7.1, with notable chitin deacetylation capabilities, was isolated from the rhizosphere of in the North Sea of China. Comparative 16S rDNA sequence analysis showed that the new isolate had the highest sequence similarity (99.79%) with CSLK01-03, followed by DSM 43338, JC435, and 10bc312 (98.97%, 98.81%, and 98.83%, respectively). Subsequent genome sequencing and phylogenetic analysis confirmed that strain T22.7.1 belongs to the species. However, additional taxonomic characterization identified strain T22.7.1 as a novel type strain of distinct from CSLK01-03.

Methods: This study refines the taxonomic description of and investigates its application in converting chitin into chitosan. The chitin deacetylase (CDA) activity of strain T22.7.1 was optimized, and the enzyme was isolated and purified from the fermentation products.

Results: Through optimization, the CDA activity of strain T22.7.1 reached 287.02 U/mL, which is 34.88 times greater than the original enzyme's activity (8.0 U/mL). The natural CDA enzyme was purified with a purification factor of 31.83, and the specific activity of the enzyme solution reached 1200.33 U/mg. CDA exhibited good pH and temperature adaptability and stability, along with a wide range of substrate adaptabilities, effectively deacetylating chitin, chitooligosaccharides, N-acetylglucosamine, and other substrates.

Discussion: Product analysis revealed that CDA treatment increased the deacetylation degree (DD) of natural chitin to 83%, surpassing that of commercial chitosan. Therefore, CDA demonstrates significant potential as an efficient deacetylation tool for natural chitin and chitooligosaccharides, highlighting its applicability in the biorefining of natural polysaccharides.