Valorisation of chitinous biomass for antimicrobial applications

The chitin and chitosan market worldwide has shown tremendous growth, propelled by the expansion in the application domain. The market volume is projected to be more than 155 thousand metric tons by the year 2022. The global market for chitin and chitosan derivatives is expected to reach $4.2 billion by 2021 up from $2.0 billion in 2016 at a compound annual growth rate (CAGR) of 15.4 %, from 2016 to 2021. Among chitin derivatives, chitosan is projected to offer the highest growth potential. The demand for a reliable source of high quality chitosan is rapidly increasing as new value added products enter the market. At the same time the growth of value added chitosan based products are limited by the availability of a sustainable supply chain. Antimicrobial properties are of special interest in the packaging, cosmetic, food and biomedical sector. Most of the latter applications warrants high-volume and low cost materials. However, the process chemistry for bulk chitosan manufacturing is currently not very environmentally friendly. Green technologies for chitosan modification have increased in recent years and now face the challenge of economic viability. In this review the status of antimicrobial chitosan derivatives will be reported with a critical review of the chemical technologies that would mitigate the commercialisation of these biopolymers in the antimicrobial biopolymer market sector. The amount of publications per annum has increased exponentially and the lack of global standardised antimicrobial test protocols make it rather challenging to properly evaluate the relative efficacy of these polymers.