Pretreatment of Low-Density Polyethylene(LDPE)with physicochemical methods before biodegradation has been demonstrated as an effective strategy.The pretreatment of LDPE exhibited alterations in molecular structure,red...Pretreatment of Low-Density Polyethylene(LDPE)with physicochemical methods before biodegradation has been demonstrated as an effective strategy.The pretreatment of LDPE exhibited alterations in molecular structure,reducing hydrophobicity and decreasing tensile strength.Additionally,pretreating LDPE enhanced microbial biodegradability to improve biofilm formation and significantly reduced the physical weight of LDPE film.AS3–8 consortia exhibited a maximum weight loss of 8.0%±0.5%after 45 days of incubation.While Bacillus sp.AS3 and Sphingobacterium sp.AS8 demonstrated LDPE weight loss of 5.03%±1.6%and 1.6%±0.5%,respectively.The structure of LDPE was altered after incubation with the bacterial strains,resulting in a reduction in the intensity of functional groups,including C=O,C=C,N–H,and C–N.The carbonyl index(CI)of LDPE also decreased by 7.17%after the consortia AS3–8 degradation.Consortia AS3–8 significantly impacted the physical properties of LDPE by reducing the water contact angle(WCA),decreasing to 64.21°±3.69°,and tensile strength(TS),decreasing to 17.97±0.3 MPa.Moreover,the esterase activity was measured through 45 days of incubation.SDS-PAGE analysis of the AS3–8 consortia revealed bands at 35,48,and 70 kDa molecular weights,similar to known enzymes like laccase and esterase.Furthermore,SEM observations showed rough,cracked surfaces on pretreated LDPE,with biofilms present after incubation with the bacterial strains.GC–MS analysis revealed that AS3–8 consortia produced depolymerized chemicals,including alkanes,aldehydes,and esters.The LDPE biodegradation pathway was elucidated.This study addresses critical knowledge gaps in improving plastic degradation efficiency.展开更多
Tomato seedlings damping-off is a limiting factor in commercial greenhouse production. To determine the causal agents of disease, sampling and fungal isolation were performed during 2012. Samples were collected from i...Tomato seedlings damping-off is a limiting factor in commercial greenhouse production. To determine the causal agents of disease, sampling and fungal isolation were performed during 2012. Samples were collected from infected seedlings growing in greenhouses in the Syrian coastal region. Isolation of fungi was done in the laboratories of the Agronomical Reaserch Center, in Lattakia and the molecular analyses were done in the Biotechnology Center at Tishreen University, Lattakia, Syria, during the years 2012, 2013. Eight isolates ofPythium sp. obtained were purified using hyphal tip method （named P1, P2, P3, P4, P5, P6, P7 and P8）. Isolates were morphologically identified by optical microscope, then molecularly Characterized using genus specific ITS primers. The results of morphological characterization of pathogenic species suggested the detection of Pythium aphanidermatum, P. ultimum. The analysis of DNAs from the different isolates with ITS primers, recognizing the inter transcript spacer of nuclear ribosomal DNA proved that the eight, isolates were belonging to the species P. ultimum. The complete sequences of ribosomal DNA internal transcribed spacers regions of selected isolates were determined and submitted to GenBank. The GenBank-BLAST homology search revealed P. ultimum as the most similar sequence （〉 96% identity） with GenBank entry AB355596.展开更多
文摘Pretreatment of Low-Density Polyethylene(LDPE)with physicochemical methods before biodegradation has been demonstrated as an effective strategy.The pretreatment of LDPE exhibited alterations in molecular structure,reducing hydrophobicity and decreasing tensile strength.Additionally,pretreating LDPE enhanced microbial biodegradability to improve biofilm formation and significantly reduced the physical weight of LDPE film.AS3–8 consortia exhibited a maximum weight loss of 8.0%±0.5%after 45 days of incubation.While Bacillus sp.AS3 and Sphingobacterium sp.AS8 demonstrated LDPE weight loss of 5.03%±1.6%and 1.6%±0.5%,respectively.The structure of LDPE was altered after incubation with the bacterial strains,resulting in a reduction in the intensity of functional groups,including C=O,C=C,N–H,and C–N.The carbonyl index(CI)of LDPE also decreased by 7.17%after the consortia AS3–8 degradation.Consortia AS3–8 significantly impacted the physical properties of LDPE by reducing the water contact angle(WCA),decreasing to 64.21°±3.69°,and tensile strength(TS),decreasing to 17.97±0.3 MPa.Moreover,the esterase activity was measured through 45 days of incubation.SDS-PAGE analysis of the AS3–8 consortia revealed bands at 35,48,and 70 kDa molecular weights,similar to known enzymes like laccase and esterase.Furthermore,SEM observations showed rough,cracked surfaces on pretreated LDPE,with biofilms present after incubation with the bacterial strains.GC–MS analysis revealed that AS3–8 consortia produced depolymerized chemicals,including alkanes,aldehydes,and esters.The LDPE biodegradation pathway was elucidated.This study addresses critical knowledge gaps in improving plastic degradation efficiency.
文摘Tomato seedlings damping-off is a limiting factor in commercial greenhouse production. To determine the causal agents of disease, sampling and fungal isolation were performed during 2012. Samples were collected from infected seedlings growing in greenhouses in the Syrian coastal region. Isolation of fungi was done in the laboratories of the Agronomical Reaserch Center, in Lattakia and the molecular analyses were done in the Biotechnology Center at Tishreen University, Lattakia, Syria, during the years 2012, 2013. Eight isolates ofPythium sp. obtained were purified using hyphal tip method （named P1, P2, P3, P4, P5, P6, P7 and P8）. Isolates were morphologically identified by optical microscope, then molecularly Characterized using genus specific ITS primers. The results of morphological characterization of pathogenic species suggested the detection of Pythium aphanidermatum, P. ultimum. The analysis of DNAs from the different isolates with ITS primers, recognizing the inter transcript spacer of nuclear ribosomal DNA proved that the eight, isolates were belonging to the species P. ultimum. The complete sequences of ribosomal DNA internal transcribed spacers regions of selected isolates were determined and submitted to GenBank. The GenBank-BLAST homology search revealed P. ultimum as the most similar sequence （〉 96% identity） with GenBank entry AB355596.
