Lack of functional polyester-biodegrading potential in marine versus terrestrial environments evidenced by an innovative airbrushing technique

Biodegradable plastics, primarily aliphatic polyesters, degrade to varying extents in different environments. However, the absence of easily implementable techniques for screening microbial biodegradation potential --coupled with the limitations of non-functional omics analyses-- has restricted comparative studies across diverse polymer types and ecosystems. In this study, we optimized a novel airbrushing method that facilitates functional analyses by simplifying the preparation of polyester-coated plates for biodegradation screening. By repurposing an airbrush kit, polyester microparticles (MPs) could be evenly sprayed onto solid media, enabling rapid detection of extracellular depolymerizing activity via clearing zone halos. This technique was effective in screening both isolated microbial cultures and natural environmental samples, demonstrating its versatility. The method was successfully applied across multiple environments, ranking the biodegradability of six polyesters, from most to least biodegradable: polycaprolactone (PCL), poly[(R)-3-hydroxybutyrate] (PHB), poly(butylene succinate) (PBS), poly(ethylene succinate) (PES), poly(lactic acid) (PLA), and poly(butylene adipate-co-terephthalate) (PBAT). Most notably, it revealed a consistent 1,000-fold higher biodegradation potential in terrestrial compared to marine environments. This approach offers a valuable tool for isolating novel polyester-degrading microbes with significant biotechnological potential, paving the way for improved plastic waste management solutions. SYNOPSISScreening polyester-degrading microbes has traditionally been challenging due to the difficulty of incorporating polyesters into solid media. This study introduces an innovative airbrush spraying method that simplifies the preparation of polyester MPs on solid media plates, making the screening process significantly more efficient. Using this method, we demonstrated the differential biodegradability of aliphatic polyesters across environments. The results revealed a stark contrast in biodegrading potential, with terrestrial ecosystems exhibiting substantially higher activity compared to marine environments. Abstract graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/622231v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@176883eorg.highwire.dtl.DTLVardef@eab2aforg.highwire.dtl.DTLVardef@792bbdorg.highwire.dtl.DTLVardef@126ab7d_HPS_FORMAT_FIGEXP M_FIG C_FIG