Is chitosan environment-friendly?
Chitosans are easily and quickly biodegraded in the environment due to the widespread occurrence of chitosan-degrading enzymes such as chitinases and chitosanases. Thus, using e.g. chitosan-based plant strengtheners in agriculture does not pose any environmental risk. Of course, like any other treatment, chitosans will influence the composition of the microflora in the soil, transiently favoring growth of chitinolytic and chitosanolytic microbes (and, thus, indirectly inhibiting chitin or chitosan containing microbes such as potentially pathogenic fungi), but these effects appear to be beneficial for the crop plants. However, a comprehensive assessment of the environment-friendliness of any compound needs to take into account also the direct and indirect effects on the environment of its production processes. Recently, the first Life Cycle Assessment of different chitosans has been performed showing that chitosans can be truly environment-friendly if a sophisticated, highly energy-efficient process is used and if extensive waste-water treatment and recycling is established.