In vitro studies on the degradation of poly(cis-1,4-isoprene)

Area of Science:

• Biotechnology
• Polymer Science
• Biocatalysis

Background:

• Poly(cis-1,4-isoprene) is a widely used natural rubber polymer.
• Efficient degradation methods for solid rubber are crucial for recycling and material modification.
• Enzymatic approaches offer potential for sustainable polymer processing.

Purpose of the Study:

• To investigate the cleavage of solid poly(cis-1,4-isoprene) using latex clearing protein (Lcp1VH2).
• To compare different strategies for enzyme addition to optimize degradation.
• To characterize the degradation products and elucidate the enzymatic mechanism.

Main Methods:

• Utilized a 200-mL enzyme reactor for solid rubber degradation.
• Employed two Lcp1VH2 addition strategies: daily low-dose vs. single high-dose.
• Analyzed degradation products using ESI-MS, GPC, HPLC-MS, and ATR-FTIR.
• Measured oxygen consumption to demonstrate oxygenase activity.

Main Results:

• Daily addition of Lcp1VH2 (50 µg mL⁻¹ for 5 days) was superior to a single dose.
• Identified soluble oligo(cis-1,4-isoprene) molecules (1-11 isoprene units, Mn = 885 g mol⁻¹) as degradation products.
• Confirmed oxygenase activity of Lcp1VH2 by measuring oxygen consumption.
• Detected carbonyl groups on the polymer surface, indicating cleavage.

Conclusions:

• Lcp1VH2 effectively cleaves solid poly(cis-1,4-isoprene) in a cell-free bioprocess.
• Optimized enzyme addition strategy enhances degradation efficiency.
• This enzymatic method provides a novel approach for partial rubber degradation and potential material treatment.