Chitosan Oligosaccharide Production Potential of Mitsuaria sp. C4 and Its Whole-Genome Sequencing

Secretory production and characterization of a highly effective chitosanase from Streptomyces coelicolor A3(2) M145 in Pichia pastoris

In this study, a glycoside hydrolase family 46 chitosanase from Streptomyces coelicolor A3(2) M145 was firstly cloned and expressed in Pichia pastoris GS115 (P. pastoris GS115). The recombinant enzyme (CsnA) showed maximal activity at pH 6.0 and 65°C. Both thermal stability and pH stability of CsnA expressed in P. pastoris GS115 were significantly increased compared with homologous expression in Streptomyces coelicolor A3(2). A stable chitosanase activity of 725.7 ± 9.58 U mL-1 was obtained in fed-batch fermentation. It's the highest level of CsnA from Streptomyces coelicolor expressed in P. pastoris so far. The hydrolytic process of CsnA showed a time-dependent manner. Chitosan oligosaccharides (COSs) generated by CsnA showed antifungal activity against Fusarium oxysporum sp. cucumerinum (F. oxysporum sp. cucumerinum). The secreted expression and hydrolytic performance make the enzyme a desirable biocatalyst for industrial controllable production of chitooligosaccharides with specific degree of polymerization, which have potential to control fungi that cause important crop diseases.

Chitosan and chito-oligosaccharide: a versatile biopolymer with endless grafting possibilities for multifarious applications

Chito-oligosaccharides (COS), derived from chitosan (CH), are attracting increasing attention as drug delivery carriers due to their biocompatibility, biodegradability, and mucoadhesive properties. Grafting, the process of chemically modifying CH/COS by adding side chains, has been used to improve their drug delivery performance by enhancing their stability, targeted delivery, and controlled release. In this review, we aim to provide an in-depth study on the recent advances in the grafting of CH/COS for multifarious applications. Moreover, the various strategies and techniques used for grafting, including chemical modification, enzymatic modification, and physical modification, are elaborated. The properties of grafted CH/COS, such as stability, solubility, and biocompatibility, were reported. Additionally, the review detailed the various applications of grafted CH/COS in drug delivery, including the delivery of small drug molecule, proteins, and RNA interference therapeutics. Furthermore, the effectiveness of grafted CH/COS in improving the pharmacokinetics and pharmacodynamics of drugs was included. Finally, the challenges and limitations associated with the use of grafted CH/COS for drug delivery and outline directions for future research are addressed. The insights provided in this review will be valuable for researchers and drug development professionals interested in the application of grafted CH/COS for multifarious applications.