Abstract
This study investigated the biodegradation of natural rubber (NR), nitrile butadiene rubber (NBR), and NR/NBR blend rubber gloves over 60 days using the consortium CK. NR gloves showed the highest weight loss (62%), followed by NR/NBR blend gloves (22%) and NBR gloves (5.2%). SEM showed cracks and holes with bacterial colonization on NR and NR/NBR blend, whereas the NBR surface remained largely unchanged with negligible attachment. Viable cell counts increased in NR from 1.5 × 108 to 3.5 × 108 CFU/mL, but decreased in the NR/NBR blend and NBR from 8.2 × 108 to 1.2 × 106 and 1.2 × 108 to 3.2 × 103 CFU/mL, respectively. ATR-FTIR analysis of NR indicated degradation products, including polyisoprene oligomers and aldehydic products, suggesting oxidative cleavage of the polyisoprene backbone. NR degraded so extensively that the rubber pieces disintegrated into tiny fragments and mechanical properties were not measurable, consistent with the contact angle decrease from 65.8° to 51.2°. In contrast, the NR/NBR blend preserved part of its mechanical performance, although tensile strength, elongation at break, and force at break decreased from 18.89 to 2.5 MPa, 645 to 605%, and 5.78 to 2.5 N, respectively. NBR also showed decreases from 36.47 to 16 MPa, 565 to 71%, and 6.98 to 0.50 N. High-throughput 16S rRNA gene sequencing of the NR-degrading consortium CK identified Pseudoxanthomonas, Olivibacter, Nocardia, and other taxa presented during the rubber degradation process. These findings indicate that incorporation of NBR into NR helped preserve part of glove mechanical performance during degradation, while the presence of NR enhanced biodegradability compared with NBR.