Abstract
Polypropylene (PP) is a widely used plastic that can fragment into microplastics, raising concerns about environmental accumulation and human health, particularly through ingestion and medical exposure. These microplastics may disrupt microbiota and intestinal function, highlighting the need to explore microbial interactions and biodegradation potential. Although probiotics are increasingly recognised for their benefits to gut health, their potential to degrade microplastics, particularly PP, remains largely unexplored. To address this gap, the present study evaluates the ability of Bifidobacterium bifidum BCMC® 12130, Bifidobacterium longum BCMC® 02120, and Bifidobacterium longum subsp. infantis BCMC® 02129 to biodegrade PP powder and commercially available PP film under controlled laboratory conditions. Bacterial growth was screened in Bushnell-Haas broth (BHB) containing varying PP concentrations, followed by incubation at 25℃ with agitation. The results identified 0.10% (w/v) PP as the optimal concentration, and B. longum BCMC® 02120 demonstrated significant degradation, achieving an 86.7% reduction in PP mass after 30 days (P < 0.05). Scanning electron microscopy revealed dense biofilm formation alongside surface roughening, voids, and erosion, consistent with microbial colonisation and deterioration of the polymer surface. Energy-dispersive X-ray spectroscopy showed a decrease in surface carbon content from 92.62% to 90.00% and an increase in oxygen content from 7.38% to 10.00%, suggesting possible surface oxidation. Together, these preliminary findings suggest that the probiotic strain B. longum BCMC® 02120 has potential for PP microplastic biodegradation. Further studies are needed to confirm polymer breakdown and determine whether this activity could help mitigate microplastic-related effects on gut health.