Advances and challenges in enzymatic rubber degradation: Exploring genetic, molecular, and biotechnological aspects

Rubber waste is one of the most persistent solid wastes of our times, mostly represented by end-of-life tires. While the biological origin of natural rubber makes it biodegradable, many tire components are not, and they make enzymatic attack by microorganisms extremely difficult. Despite the great multi-enzymatic catabolic capacity of various bacteria and fungi, there are currently no organisms or enzymes capable of effectively degrading vulcanized tire waste. However, biotechnological advances in enzymatic rubber degradation processes are opening new opportunities. The diversity of rubber oxygenases, the transcriptional regulation of their corresponding genes, and the downstream oxidation of oligo-isoprene aldehydes are also discussed in this review. This biotransformation is positioned as a potential enzymatic upcycling of rubber wastes. Although there have been significant advances at the molecular and bioprocess levels, there are several obstacles that must be solved to propose an efficient and scalable process.