Preparation of pH-Responsive Alginate-Chitosan Microspheres for L-Valine Loading and Their Effects on the A40926 Production

Application of chitosan/alginate nanoparticle in oral drug delivery systems: prospects and challenges

Oral drug delivery systems (ODDSs) have various advantages of simple operation and few side effects. ODDSs are highly desirable for colon-targeted therapy (e.g. ulcerative colitis and colorectal cancer), as they improve therapeutic efficiency and reduce systemic toxicity. Chitosan/alginate nanoparticles (CANPs) show strong electrostatic interaction between the carboxyl group of alginates and the amino group of chitosan which leads to shrinkage and gel formation at low pH, thereby protecting the drugs from the gastrointestinal tract (GIT) and aggressive gastric environment. Meanwhile, CANPs as biocompatible polymer, show intestinal mucosal adhesion, which could extend the retention time of drugs on inflammatory sites. Recently, CANPs have attracted increasing interest as colon-targeted oral drug delivery system for intestinal diseases. The purpose of this review is to summarize the application and treatment of CANPs in intestinal diseases and insulin delivery. And then provide a future perspective of the potential and development direction of CANPs as colon-targeted ODDSs.

Production enhancement of the glycopeptide antibiotic A40926 by an engineered Nonomuraea gerenzanensis strain

OBJECTIVE

To improve the production of A40926, a combined strategy of constructing the engineered strain and optimizing the medium was implemented.

RESULTS

The engineered strain lcu1 with the genetic features of dbv23 deletion and dbv3-dbv20 coexpression increased by 30.6% in the production of A40926, compared to the original strain. In addition, a combined medium called M9 was designed to be further optimized by the central composite design method. The optimized M9 medium was verified to significantly improve the A40926 yield from 257 to 332 mg l^-1.

CONCLUSIONS

The engineered strain lcu1 could significantly promote A40926 production in the optimized M9 medium, which indicated that the polygenic genetic manipulation and the media optimization played an equally important role in increasing the A40926 yield.

Preparation of Alginate-Based Biomaterials and Their Applications in Biomedicine

Alginates are naturally occurring polysaccharides extracted from brown marine algae and bacteria. Being biocompatible, biodegradable, non-toxic and easy to gel, alginates can be processed into various forms, such as hydrogels, microspheres, fibers and sponges, and have been widely applied in biomedical field. The present review provides an overview of the properties and processing methods of alginates, as well as their applications in wound healing, tissue repair and drug delivery in recent years.