Frank R

References (7)

Title : Structure and function of the metagenomic plastic-degrading polyester hydrolase PHL7 bound to its product - Richter_2023_Nat.Commun_14_1905
Author(s) : Richter PK , Blazquez-Sanchez P , Zhao Z , Engelberger F , Wiebeler C , Kunze G , Frank R , Krinke D , Frezzotti E , Lihanova Y , Falkenstein P , Matysik J , Zimmermann W , Strater N , Sonnendecker C
Ref : Nat Commun , 14 :1905 , 2023
Abstract : The recently discovered metagenomic-derived polyester hydrolase PHL7 is able to efficiently degrade amorphous polyethylene terephthalate (PET) in post-consumer plastic waste. We present the cocrystal structure of this hydrolase with its hydrolysis product terephthalic acid and elucidate the influence of 17 single mutations on the PET-hydrolytic activity and thermal stability of PHL7. The substrate-binding mode of terephthalic acid is similar to that of the thermophilic polyester hydrolase LCC and deviates from the mesophilic IsPETase. The subsite I modifications L93F and Q95Y, derived from LCC, increased the thermal stability, while exchange of H185S, derived from IsPETase, reduced the stability of PHL7. The subsite II residue H130 is suggested to represent an adaptation for high thermal stability, whereas L210 emerged as the main contributor to the observed high PET-hydrolytic activity. Variant L210T showed significantly higher activity, achieving a degradation rate of 20 microm h(-1) with amorphous PET films.
ESTHER : Richter_2023_Nat.Commun_14_1905
PubMedSearch : Richter_2023_Nat.Commun_14_1905
PubMedID: 37019924
Gene_locus related to this paper: 9firm-PHL7

Title : Low Carbon Footprint Recycling of Post-Consumer PET Plastic with a Metagenomic Polyester Hydrolase - Sonnendecker_2022_ChemSusChem_15_e202101062
Author(s) : Sonnendecker C , Oeser J , Richter PK , Hille P , Zhao Z , Fischer C , Lippold H , Blazquez-Sanchez P , Engelberger F , Ramirez-Sarmiento CA , Oeser T , Lihanova Y , Frank R , Jahnke HG , Billig S , Abel B , Strater N , Matysik J , Zimmermann W
Ref : ChemSusChem , 15 :e202101062 , 2022
Abstract : Our planet is flooded with plastics and the need for sustainable recycling strategies of polymers has become increasingly urgent. Enzyme-based hydrolysis of post-consumer plastic is an emerging strategy for closed-loop recycling of polyethylene terephthalate (PET). The polyester hydrolase PHL7 isolated from a compost metagenome completely hydrolyzed amorphous PET films, releasing 91 mg of terephthalic acid per hour and mg of enzyme. Degradation rates of the PET film of 6.8 microm h -1 were monitored by vertical scanning interferometry. Structural analysis indicated the importance of leucine at position 210 for the extraordinarily high PET-hydrolyzing activity of PHL7. Within 24 h, 0.6 mg enzyme g PET -1 completely degraded post-consumer thermoform PET packaging in an aqueous buffer at 70 degreesC without any energy-intensive pretreatments. Terephthalic acid recovered from the enzymatic hydrolysate was used to synthesize virgin PET, demonstrating the potential of polyester hydrolases as catalysts in sustainable PET recycling processes with a low carbon footprint.
ESTHER : Sonnendecker_2022_ChemSusChem_15_e202101062
PubMedSearch : Sonnendecker_2022_ChemSusChem_15_e202101062
PubMedID: 34129279
Gene_locus related to this paper: 9firm-PHL7

Title : Real-Time Noninvasive Analysis of Biocatalytic PET Degradation - Frank_2022_ACS.Catal_12_25
Author(s) : Frank R , Krinke D , Sonnendecker C , Zimmermann W , Jahnke HG
Ref : ACS Catal , 12 :25 , 2022
Abstract : The Earth has entered the Anthropocene, which is branded by ubiquitous and devastating environmental pollution from plastics such as polyethylene terephthalate (PET). Ecofriendly and at the same time economical solutions for plastic recycling and reuse are being sought more urgently now than ever. With the possibility to recover its building blocks, the hydrolysis of PET waste by its selective biodegradation with polyester hydrolases is an appealing solution. We demonstrate how changing the dielectric properties of PET films can be used to evaluate the performance of polyester hydrolases. For this purpose, a PET film separates two reaction chambers in an impedimetric setup to quantify the film thickness- and surface area-dependent change in capacitance caused by the enzyme. The derived degradation rates determined for the polyester hydrolases PHL7 and LCC were similar to those obtained by gravimetric and vertical scanning interferometry measurements. Compared to optical methods, this technique is also insensitive to changes in the solution composition. AFM and FEM simulations further supported that impedance spectroscopy is a powerful tool for the detailed analysis of the enzymatic hydrolysis process of PET films. The developed monitoring system enabled both high-temporal resolution and parallel processing suitable for the analysis of the enzymatic degradability of polyester films and the properties of the biocatalysts.
ESTHER : Frank_2022_ACS.Catal_12_25
PubMedSearch : Frank_2022_ACS.Catal_12_25
Gene_locus related to this paper: 9firm-PHL7 , 9bact-g9by57

Title : Microfluidic Free-Flow Electrophoresis Based Solvent Exchanger for Continuously Operating Lab-on-Chip Applications - Zitzmann_2017_Anal.Chem_89_13550
Author(s) : Zitzmann FD , Jahnke HG , Pfeiffer SA , Frank R , Nitschke F , Mauritz L , Abel B , Belder D , Robitzki AA
Ref : Analytical Chemistry , 89 :13550 , 2017
Abstract : For miniaturization and integration of chemical synthesis and analytics on small length scales, the development of complex lab-on-chip (LOC) systems is in the focus of many current research projects. While application specific synthesis and analytic modules and LOC devices are widely described, the combination and integration of different modules is intensively investigated. Problems for in-line processes such as solvent incompatibilities, e.g., for a multistep synthesis or the combination of an organic drug synthesis with a cell-based biological activity testing system, require a solvent exchange between serialized modules. Here, we present a continuously operating microfluidic solvent exchanger based on the principle of free-flow electrophoresis for miscible organic/aqueous fluids. We highlight a proof-of-principle and describe the working principle for the model compound fluorescein, where the organic solvent DMSO is exchanged against an aqueous buffer. The DMSO removal performance could be significantly increased to 95% by optimization of the microfluidic layout. Moreover, the optimization of the inlet flow ratio resulted in a minimized dilution factor of 5, and we were able to demonstrate that a reduction of the supporting instrumentation is possible without a significant decrease of the DMSO removal performance. Finally, the compatibility of the developed solvent exchanger for cell based downstream applications was proven. The impedimetric monitoring of HEK293A cells in a continuously operating microfluidic setup revealed no adverse effects of the residual DMSO after the solvent replacement. Our solvent exchanger device demonstrates the power of micro-free-flow electrophoresis not only as a powerful technique for separation and purification of compound mixtures but also for solvent replacement.
ESTHER : Zitzmann_2017_Anal.Chem_89_13550
PubMedSearch : Zitzmann_2017_Anal.Chem_89_13550
PubMedID: 29164853

Title : Residues of insecticides, and fungicides in fruit produced in Ontario, Canada, 1986-1988 - Frank_1990_Food.Addit.Contam_7_637
Author(s) : Frank R , Braun HE , Ripley BD
Ref : Food Additives & Contaminants , 7 :637 , 1990
Abstract : Between 1986 and 1988, 306 composite samples of fruit representing eight commodities were collected from farm deliveries to the marketplace in Ontario, Canada. All samples were analysed for insecticides and fungicides. The analysis procedure included tests for organochlorine, organophosphorus, synthetic pyrethroid and methylcarbamate insecticides and dithiocarbamate, dicarboximide and organochlorine fungicides. The commodities tested included apples, blueberries, cherries, grapes, peaches, pears, raspberries and strawberries. In 14% of all fruit samples, pesticide residues were below the detection limits, which ranged between 0.005 and 0.02 mg/kg. A further 14% had total combined pesticide residues below 0.1 mg/kg. Total combined fungicide and insecticide residues ranged from 0.1 to 11 mg/kg in 72% of samples. Six different pesticides were in violation of maximum residue limits (MRL) on 11 (3.6%) of fruit samples. Captan exceeded the 5 mg/kg MRL in five samples and EBDC exceeded the 7 mg/kg MRL in two. Other violations included single fruit samples with dicofol, endosulphan, phosalone and iprodione above the MRL. Raw grapes harvested for wine contained residues of 10 pesticides and the number changed little following the crushing of the grapes; however, fermentation into wine significantly reduced residues. Six insecticides and four fungicides were present on the raw grapes and 4/105 were above the MRL. Following crushing, four insecticides and five fungicides were identified and 4/40 were above the MRL. In wine only three insecticides were identified and all were well below the MRL. Carbaryl appeared to be the most persistent, declining very little between raw grapes and wine.
ESTHER : Frank_1990_Food.Addit.Contam_7_637
PubMedSearch : Frank_1990_Food.Addit.Contam_7_637
PubMedID: 2253808

Title : Monitoring Ontario-grown apples for pest control chemicals used in their production, 1978-86 - Frank_1989_Food.Addit.Contam_6_227
Author(s) : Frank R , Braun HE , Ripley BD
Ref : Food Additives & Contaminants , 6 :227 , 1989
Abstract : Between 1978 and 1986, 305 samples of apples were monitored for the residues of a wide range of pesticides used in their production. Three (1%) contained residues above the maximum residue limits (MRL) permitted under the Canadian Food and Drug Act and regulations; two involved phosalone at 5.9 and 6.2 mg/kg respectively and one involved diphenylamine at 6.7 mg/kg when the MRL was 5.0 mg/kg for both compounds. Low residues of dicofol, endosulfan, phosalone, phosmet, captan, daminozide and diphenylamine were frequently found; however they were well below the MRLs. These residue levels were correlated with survey data on the areas of the apple crop treated with specific pesticides. Residues of carbaryl, diazinon, ethion, azinophosmethyl, parathion, and dithiocarbamate fungicides were found occasionally; all were well below the MRLs and correlated with the pattern of use. No residues of PCB were found to a limit of detection of 0.01 mg/kg.
ESTHER : Frank_1989_Food.Addit.Contam_6_227
PubMedSearch : Frank_1989_Food.Addit.Contam_6_227
PubMedID: 2924979

Title : Foliar pesticide residues in relation to worker re-entry - McEwen_1980_Pest.Sci_11_643
Author(s) : McEwen FL , Ritcey G , Braun H , Frank R , Ripley BD
Ref : Pest Sci , 11 :643 , 1980
Abstract : Residues were determined at 8-h intervals during the 48 h after application of endosulfan, leptophos, methamidophos, methomyl and mevinphos to head lettuce; of endosulfan, methamidophos and methomyl to cauliflower; and of parathion to onions and carrots. Residues of phosalone and parathion were measured on apple leaves 0, 1, 2, 4, 8 and 16 days after application. In addition, the portion of the residue on apple leaves that could be dislodged was measured, as well as the residues on gloves used to handle the apple foliage. There were large differences in the rates of disappearance of the insecticides, differences that must be known in determining safe re-entry periods for workers.
ESTHER : McEwen_1980_Pest.Sci_11_643
PubMedSearch : McEwen_1980_Pest.Sci_11_643