Chitosan Oligosaccharide：Zhongke Runyao to explore ways to industrialize research achievements on virus and cold resistant

Saccharide is a very important biological macromolecule in the field of life sciences. Saccharide bioengineering technology is the third-largest biological technology in human history after genetic engineering and protein engineering. Saccharide bioengineering technology will focus on a carbohydrate chain sequencing and synthesis technology development, covering the efficiency, reliability, operability and universality of the de novo sequencing of carbohydrate chain and sequencing of the carbohydrate chain micro samples. These factors will determine and guide research into the carbohydrate chain’s relationship between structure and function. 

The industrial value of the carbohydrate chain is not just limited to contributing to biomedicine and human health but is also of great significance to plant health, especially in the carbohydrate chain and plant immunology studies. AgroPages has had an interview with Zhao Yong, Ph.D. of Institute of Process Research, Chinese Academy of Sciences, General Manager at Zhongke Runyao, to understand his Chitosan Oligosaccharide research and application practices over the last 20 years.

Could you explain to us the difference between Chitin, Chitosan and Chitosan Oligosaccharide as well as their respective applications in agriculture, especially the application of the last-named?

Chitin and Chitosan are polysaccharides, which come mainly from shrimp and crab shells, insect shells and fungal cell walls, representing one of the most abundant biomasses in the natural world. Chitin is not easily soluble in water or conventional organic solvents. It is deacetylated at high temperatures, resulting in a Chitosan which is not easily soluble in water but can dissolve in weak acid. Chitosan Oligosaccharide, via acid hydrolysis or enzymatic hydrolysis, can result in one of lower molecular weight which is easily soluble in water. Therefore, it is the most widely used product in agriculture. As a plant immune inducer or biostimulant, Chitosan Oligosaccharide has been used in China for more than 20 years.

Chitosan Oligosaccharide is not a plant nutrient, but it can indirectly increase a plant’s absorption of nutrients by improving its roots, thus indirectly improving its nutrition. Chitosan Oligosaccharide is not a conventional targeting pesticide, but it activates the pattern triggered immunity (PTI) of plants, improves the response-ability of plants against biological stress (diseases and pests) and abiotic stress (low temperature, drought, saline-alkali), enhances the disease resistance and stress resistance of plants and regulates the use of chemical pesticides. When being used with chemical pesticides, it creates a synergistic effect.

After years of exploration and practising, Chitosan Oligosaccharide is positioned firstly for use of prevention and control of plant viruses, followed by mixing with fosthiazate and avermectins for control of nematodes. In my opinion, going forward, in China, it will still be used for synergistic purposes in mixed-use with chemical pesticides, where it will be used to improve quality and efficiency.

Zhongke Runyao made Chitosan Oligosaccharide via Chitosanase. Compared with traditional acid degradation and oxidative degradation, what are the advantages and technical difficulties of this method?

There are three methods to make Chitosan Oligosaccharide: chemical, physical, and biological. At present, the main one is the biological enzyme method, which is more acceptable to the market perhaps as a result of superior marketing. The key issue is that it is not the best because of its biological enzyme method, but because the key is in the structural characteristics of the Chitosan Oligosaccharide produced. According to conclusive evidence, although all Chitosan Oligosaccharides are produced via the same enzymatic method, the activity of the products can vary greatly. On the other side, the users of Chitosan Oligosaccharide often cannot analyze the structure to distinguish the pros and cons. So, there is often feedback from users that says Chitosan Oligosaccharides produces an unstable effect. The essential reason for this lies in the control of the structure of Chitosan Oligosaccharide, which decides its stability and function.

The structure of Chitosan Oligosaccharide is complicated and represented by the different lengths of the carbohydrate chain, with a difference of degrees of the deacetylation GlcNAc monosaccharide and GlcN monosaccharide as well as the diversified sequences of acetylation. Although Chitosan Oligosaccharide has various functions and can be used broadly, the different structural characteristics are set to correspond to a different mechanism.

Figure 1: Structure of Chitosan Oligosaccharide with different degrees of polymerization

The Chitosan Oligosaccharide of Zhongke Runyao has been evolving innovatively for more than 20 years and has gone through many technological iterations. In the process of innovation, four factors have been considered in making high-quality and high-activity Chitosan Oligosaccharides: raw material, tool enzyme, technical process and structure-oriented mechanism.

Please share with us a detailed application and effect of chitosan oligosaccharide.

Induced antiviral treatment is the first market position given to Chitosan Oligosaccharide. With a 50μg/mL application of Chitosan oligosaccharide, a crop’s disease index rate drops to 85.45%. Similar test results were achieved in its application to tobacco, papaya, cucumber and chilli. Chitosan Oligosaccharide’s control effect on fungal diseases ranges between 40% and 85%, which reveals its broad-spectrum effect. When being mixed for use with targeted fungicides, both internal and external effects are achieved, which facilitates the implementation of the strategy of “reduction of use and increase of efficiency.” 

Fungicides support mixed-use of pyraclostrobin, ethylicin, tebuconazole and phenamacril. Furthermore, Chitosan Oligosaccharide is found to have a new function, which degrades pesticide residues.

Figure 2: Tobacco induced antiviral test (left) and cucumber powdery mildew test (right)

In addition to laboratory tests, the work team of Zhongke Runyao has established long-term exploration-related collaborations with domestic well-known biopesticide companies, fertilizer manufacturers and local government’s plant protection offices. For example, in the potato field application in cooperation with Beijing Multigrass Formulation’s technical executive Zhang Jianbo, the spraying of 3% of Chitosan Oligosaccharide at fivefold solutions resulted in a 75% rate of control of potato black scurf, which is better and more cost-effective than using imported fungicide. Moreover, it shows 70% rate of control of early blight. It is evident in the field that the root system is more developed, while the incidence of stem rot is quite reduced. 

Figure 3: Blank control of Chitosan Oligosaccharide treatment and kresoxim-methyl treatment 

What is the core competitiveness and product advantage of Zhongke Runyao?

Zhongke Runyao is a technology-driven enterprise derived from the Institute of Process Research, Chinese Academy of Sciences and jointly incubated by Suzhou Municipal Government, focusing on R & D, production and sales of high-quality oligosaccharides. At present, the company has built a production line with an annual output of 300 tons of Chitosan Oligosaccharides and 6,000 tons of formulations. Compared to a business scale, the company pays more attention to product quality and user value. During China’s 13th Five-Year Plan period, the company focused on R & D activities which are already the company’s corporate strength, having successively created three new structured oligosaccharides – DA - resistance inducer, Chitosan Oligosaccharide and Alginate Oligosaccharide. Each oligosaccharide with a different structure is uniquely positioned for different functions: Alginate Oligosaccharide, which boosts rooting, is an excellent fertilizer synergist; DA-inducer is very strong as an insect-resistant; Chitosan Oligosaccharide induces cold resistance and resistance to virus, fungi and nematode.

Firstly, any pesticide or fertilizer company needs to develop good, competitive products, while good products do work out well without high-quality raw materials. But not many people can address the issue of ‘why is this raw material good?’ very clearly. Secondly, the quality of raw materials needs to be re-verified on multiple occasions in the course of processing.

Zhongke Runyao has always adopted its “subtraction method”, which is concentrated only on the oligosaccharide raw materials, having dedicatedly practised research for more than 20 years in oligosaccharide research, development and application technology. Comparatively speaking, we have more advantages and experiences in R & D and the creation of better oligosaccharides. Hence, we are in a better position to say why it is good and how to make it good; and we know how to better help users to make the most of it and also help them solve problems to the maximum. I think that is our core competitiveness.