A simple and rapid colorimetric method for the estimation of chitosan produced by microbial degradation of chitin...

Chitin is one of the most abundant biopolymers present in the environment. Chitosan being its major derivative can be obtained by hydrolysis of chitin, especially by microbial degradation. Estimation of resulting chitosan produced by chitin degradation is crucial to the process. Usefulness of the method of Badawy (Badawy, 2012) for estimation of chitosan is limited by interference resulting from susceptibility to variation in the pH of the sample and thiobarbituric acid. This work presents an improvement of the method proposed by Badawy for colorimetric determination of chitosan by using 3, 5-Dinitrosalicylic acid (DNSA) reagent instead of thiobarbituric acid, after one step depolymerization and deamination of chitosan with sodium nitrite (NaNO₂). Eventually colorimetric estimation was carried out at 540 nm. With the use of DNSA reagent, the limitation of thiobarbituric acid are overcome. This method is easy, cost effective, and sensitive for quantitative determination of chitosan. This new improved method was applied for evaluation and quantification of chitosan produced by microbial degradation of chitin waste by different novel Streptomyces strains.