Isolation of plastic-degrading Gram-positive bacteria from Mosul Environment-Iraq

Plastic accumulation cause ecological problems effect on health, due to non-solubility of plastic in water, bacteria play role in degradation polymer, This study aimed to isolate and identify bacterial species which possessed capability in degrading polyethylene terephthalate (PET) represented by water bottle and low density polyethylene(LDPE) represented by shopping black bags, eleven soil samples were collected from soil polluted . After 4 months of incubation, 11 samples showed bacterial growth and were capable of using LDPE and PET as carbon sources, identified using the 16S rRNA sequencing technique. Six of them degraded PET were Cytobacillus firmus ZE14.iq , Bacillus thaonhiensis ZE17.iq , Bacillus subtilis ZE15.iq , Micrococcus yunnanensis ZE81.iq , Ectobacillus funiculus ZE19.iq, and Peribacillus frigoritolerans ZE20.iq , while the other five isolates degraded LDPE were Peribacillus frigoritolerans ZE13.iq , Priestia megaterium ZEV6.iq , Paenibacillus lautus ZE11.iq , Bacillus subtilis ZE16.iq , and Bacillus subtilis ZE12.iq. The degradation was detected using FTIR, GC-MS, weight loss, and SEM techniques; the FTIR spectrum showed variations in the intensity of functional groups. It formed a new chemical bond in the polymer , and the most potent ability to degrade (PET) was achieved by Cytobacillus firmus at 56%. In contrast, the highest percentage of weight loss for LDPE was 48% by Bacillus subtilis. GC-MS analysis revealed the formation of fatty acids, alcohols, Aldehydes, and other new compounds. SEM showed alterations in the physical properties of the PET surface, which degraded with bacterial treatment compared with the control plastic that was untreated with bacteria.