The essential oil from fresh and dried rhizomes of Hedychium coronarium on GC-MS analysis resulted in the identification of 44 and 38 constituents representing 93.91% and 95.41%, respectively. The major components of the essential oil from fresh and dried Hedychium coronarium rhizome were 1,8-cineole (41.42%, 37.44%), beta-pinene (10.39%, 17.4%) and alpha-terpineol (8.8%, 6.7%). The aromatic oil has antifungal as well as antibacterial effects. The antimicrobial activities of the essential oil were individually evaluated against four microorganisms, including two bacteria and two fungi. It was found that the antimicrobial activity was higher in the fresh sample than the dried. Both samples showed a better activity against Trichoderma sp. and Candida albicans than against the bacteria Bacillus subtilis and Pseudomonas aeruginosa.

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Chitosan, a natural polysaccharide, was used for the covalent immobilization of horseradish peroxidase, an enzyme of high synthetic utility, with the carbodiimide method. Of the enzyme, 62% was immobilized on chitosan when 1-ethyl-3-(3-dimethylaminopropyl carbodiimide) was used as the peptide coupling agent. The influence of different parameters, such as the enzyme concentration, carbodiimide concentration, and incubation period, on the activity retention of the immobilized enzyme was investigated. Kinetic studies using horseradish peroxidase immobilized on chitosan revealed the effects of several parameters, such as the substrate hydrophilicity and hydrophobicity, the solubility of substrates in the medium, the solvent hydrophobicity, and the support aquaphilicity, on the catalytic activity of the immobilized enzyme in nonaqueous media. General rules for the optimization of solvents for nonaqueous enzymology based on the partitioning of the solvent were not applicable for the immobilized horseradish peroxidase. The catalytic efficiency was greatest when o-phenylene diamine was used as the substrate and least when guaiacol was used. The aquaphilicity of the support played an important role in the kinetics of the immobilized horseradish peroxidase in water-miscible solvents. The results were promising for the future development of chitosan-immobilized enzymes for use in organic media.