scholarly journals Evaluation of PET Degradation Using Artificial Microbial Consortia

2021 ◽  
Vol 12 ◽  
Author(s):  
Xinhua Qi ◽  
Yuan Ma ◽  
Hanchen Chang ◽  
Bingzhi Li ◽  
Mingzhu Ding ◽  
...  
Keyword(s):  
Weight Loss ◽  
Bacillus Subtilis ◽  
Terephthalic Acid ◽  
Microbial Consortium ◽  
Microbial Consortia ◽  
Breakdown Product ◽  
Complex Polymers ◽  
Pet Film ◽  
Pet Hydrolase ◽  
Rhodococcus Jostii

Polyethylene terephthalate (PET) biodegradation is regarded as an environmentally friendly degradation method. In this study, an artificial microbial consortium composed of Rhodococcus jostii, Pseudomonas putida and two metabolically engineered Bacillus subtilis was constructed to degrade PET. First, a two-species microbial consortium was constructed with two engineered B. subtilis that could secrete PET hydrolase (PETase) and monohydroxyethyl terephthalate hydrolase (MHETase), respectively; it could degrade 13.6% (weight loss) of the PET film within 7 days. A three-species microbial consortium was further obtained by adding R. jostii to reduce the inhibition caused by terephthalic acid (TPA), a breakdown product of PET. The weight of PET film was reduced by 31.2% within 3 days, achieving about 17.6% improvement compared with the two-species microbial consortium. Finally, P. putida was introduced to reduce the inhibition caused by ethylene glycol (EG), another breakdown product of PET, obtaining a four-species microbial consortium. With the four-species consortium, the weight loss of PET film reached 23.2% under ambient temperature. This study constructed and evaluated the artificial microbial consortia in PET degradation, which demonstrated the great potential of artificial microbial consortia in the utilization of complex substrates, providing new insights for biodegradation of complex polymers.

scholarly journals Current Advances in the Biodegradation and Bioconversion of Polyethylene Terephthalate

2021 ◽  
Vol 10 (1) ◽  
pp. 39
Author(s):  
Xinhua Qi ◽  
Wenlong Yan ◽  
Zhibei Cao ◽  
Mingzhu Ding ◽  
Yingjin Yuan
Keyword(s):  
Polyethylene Terephthalate ◽  
Microbial Consortium ◽  
Tricarboxylic Acid Cycle ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Microbial Consortia ◽  
Plastic Pollution ◽  
One Step ◽  
Complex Polymers ◽  
The One

Polyethylene terephthalate (PET) is a widely used plastic that is polymerized by terephthalic acid (TPA) and ethylene glycol (EG). In recent years, PET biodegradation and bioconversion have become important in solving environmental plastic pollution. More and more PET hydrolases have been discovered and modified, which mainly act on and degrade the ester bond of PET. The monomers, TPA and EG, can be further utilized by microorganisms, entering the tricarboxylic acid cycle (TCA cycle) or being converted into high value chemicals, and finally realizing the biodegradation and bioconversion of PET. Based on synthetic biology and metabolic engineering strategies, this review summarizes the current advances in the modified PET hydrolases, engineered microbial chassis in degrading PET, bioconversion pathways of PET monomers, and artificial microbial consortia in PET biodegradation and bioconversion. Artificial microbial consortium provides novel ideas for the biodegradation and bioconversion of PET or other complex polymers. It is helpful to realize the one-step bioconversion of PET into high value chemicals.

scholarly journals A preliminary study of the degradation of selected commercial packaging materials in compost and aqueous environments

2011 ◽  
Vol 13 (1) ◽  
pp. 55-57 ◽  
Author(s):  
Marta Musioł ◽  
Joanna Rydz ◽  
Wanda Sikorska ◽  
Piotr Rychter ◽  
Marek Kowalczuk
Keyword(s):  
Molecular Weight ◽  
Weight Loss ◽  
Terephthalic Acid ◽  
Packaging Materials ◽  
Distilled Water ◽  
Abiotic Degradation ◽  
Aqueous Environments ◽  
Preliminary Study ◽  
Industrial Composting ◽  
Surface Changes

A preliminary study of the degradation of selected commercial packaging materials in compost and aqueous environmentsThe paper presents the results of the degradation of two commercial packaging materials CONS-PET and BioPlaneta in the compost and distilled water at 70°C. The materials containing polylactide (PLA), CONS-PET 13% and BioPlaneta 20%, aliphatic-aromatic copolyester terephthalic acid/adipic acid/1,4-butanediol (BTA) and commercial additives degraded under the industrial composting conditions (composting pile or container) and in distilled water at 70°C in the laboratory holding oven. Distilled water provided the conditions for the hydrolytic (abiotic) degradation of the materials. Weight loss, changes of molecular weight, dispersity monitored via the GPC technique and the macroscopic surface changes of the tested materials were monitored during the experiments. The investigated systems show similar trends of degradation, however on the last day of the incubation the decrease of the molecular weight was higher in water than under the industrial composting conditions. The results indicate that commercial packaging materials can be degraded both while composting ((bio)degradation) and during the incubation in distilled water at 70°C (abiotic hydrolysis).

Metagenomics Study To Compare The Taxonomy And Metabolism of a Lignocellulolytic Microbial Consortium Cultured in Different Carbon Conditions

2021 ◽  
Author(s):  
Qinggeer BORJIGIN ◽  
Bizhou ZHANG ◽  
Xiaofang Yu ◽  
Julin Gao ◽  
Xin ZHANG ◽  
...  
Keyword(s):  
Microbial Consortium ◽  
Agricultural Waste ◽  
Taxonomic Diversity ◽  
Taxonomic Composition ◽  
Microbial Consortia ◽  
Rich Diversity ◽  
Cazy Database ◽  
Taxonomic Affiliation ◽  
In Situ Biodegradation

Abstract A lignocellulolytic microbial consortium holds promise for the in situ biodegradation of crop straw and the comprehensive and effective utilization of agricultural waste. In this study, we applied metagenomics technology to comprehensively explore the metabolic functional potential and taxonomic diversity of the microbial consortia CS (cultured on corn stover) and FP (cultured on filter paper).Analyses of the metagenomics taxonomic affiliation data showed considerable differences in the taxonomic composition and functional profile of the microbial consortia CS and FP. The microbial consortia CS primarily contained members from the genera Pseudomonas, Stenotrophomonas, Achromobacter, Dysgonomonas, Flavobacterium and Sphingobacterium, as well as Cellvibrio, Azospirillum, Pseudomonas, Dysgonomonas and Cellulomonas in FP. The COG and KEGG annotation analyses revealed considerable levels of diversity. Further analysis determined that the CS consortium had an increase in the acid and ester metabolism pathways, while carbohydrate metabolism was enriched in the FP consortium. Furthermore, a comparison against the CAZy database showed that the microbial consortia CS and FP contain a rich diversity of lignocellulose degrading families, in which GH5, GH6, GH9, GH10, GH11, GH26, GH42, and GH43 were enriched in the FP consortium, and GH44, GH28, GH2, and GH29 increased in the CS consortium. The degradative mechanism of lignocellulose metabolism by the two microbial consortia is similar, but the annotation of quantity of genes indicated that they are diverse and vary greatly. The lignocellulolytic microbial consortia cultured under different carbon conditions (CS and FP) differed substantially in their composition of the microbial community at the genus level. The changes in functional diversity were accompanied with variation in the composition of microorganisms, many of which are related to the degradation of lignocellulolytic materials. The genera Pseudomonas, Dysgonomonas and Sphingobacterium in CS and the genera Cellvibrio and Pseudomonas in FP exhibited a much wider distribution of lignocellulose degradative ability.

scholarly journals Development of a targeted gene disruption system in the PET-degrading bacterium Ideonella sakaiensis and its applications to PETase and MHETase genes

2021 ◽  
Author(s):  
Shin-ichi Hachisuka ◽  
Tarou Nishii ◽  
Shosuke Yoshida
Keyword(s):  
Terephthalic Acid ◽  
Parent Strain ◽  
Gene Disruption ◽  
Ethylene Terephthalate ◽  
Targeted Gene Disruption ◽  
Degrading Bacterium ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Pet Hydrolase

Poly(ethylene terephthalate) (PET) is a commonly used synthetic plastic; however its non-biodegradability results in a large amount of waste accumulation that has a negative impact on the environment. Recently, a PET-degrading bacterium Ideonella sakaiensis 201-F6 strain was isolated and the enzymes involved in PET-digestion, PET hydrolase (PETase) and mono(2-hydroxyethyl) terephthalic acid (MHET) hydrolase (MHETase), were identified. Despite the great potentials of I. sakaiensis in bioremediation and biorecycling, approaches to studying this bacterium remain limited. In this study, to enable the functional analysis of PETase and MHETase genes in vivo , we have developed a gene disruption system in I. sakaiensis . The pT18 mobsacB -based disruption vector harboring directly connected 5'- and 3'-flanking regions of the target gene for homologous recombination was introduced into I. sakaiensis cells via conjugation. First, we deleted the orotidine 5'-phosphate decarboxylase gene ( pyrF ) from the genome of the wild-type strain, producing the Δ pyrF strain with 5-fluoroorotic acid (5-FOA) resistance. Next, using the Δ pyrF strain as a parent strain, and pyrF as a counterselection marker, we disrupted the genes for PETase and MHETase. The growth of both Δ petase and Δ mhetase strains on terephthalic acid (TPA, one of the PET hydrolytic products) was comparable to that of the parent strain. However, these mutant strains dramatically decreased the growth level on PET to that on no carbon source. Moreover, the Δ petase strain completely abolished PET degradation capacity. These results demonstrate that PETase and MHETase are essential for I. sakaiensis metabolism of PET. IMPORTANCE The poly(ethylene terephthalate) (PET)-degrading bacterium Ideonella sakaiensis possesses two unique enzymes able to serve in PET hydrolysis. PET hydrolase (PETase) hydrolyzes PET into mono(2-hydroxyethyl) terephthalic acid (MHET) and MHET hydrolase (MHETase) hydrolyzes MHET into terephthalic acid (TPA) and ethylene glycol (EG). These enzymes have attracted global attention as they have potential to be used for bioconversion of PET. Compared to many in vitro studies including the biochemical and crystal structure analyses, few in vivo studies have been reported. Here, we developed a targeted gene disruption system in I. sakaiensis , which was then applied for constructing Δ petase and Δ mhetase strains. Growth of these disruptants revealed that PETase is a sole enzyme responsible for PET degradation in I. sakaiensis , while PETase and MHETase play essential roles in its PET assimilation.

scholarly journals Contributions of Microbial “Contact Leaching” to Pyrite Oxidation under Different Controlled Redox Potentials

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 856
Author(s):  
Bingxu Dong ◽  
Yan Jia ◽  
Qiaoyi Tan ◽  
Heyun Sun ◽  
Renman Ruan
Keyword(s):  
Redox Potential ◽  
Dissolution Rate ◽  
Elemental Sulfur ◽  
Microbial Consortium ◽  
Pyrite Oxidation ◽  
Microbial Consortia ◽  
Redox Potentials ◽  
Sulfur Passivation ◽  
Sulfur Oxidizing ◽  
Contact Oxidation

The function of microbial contact leaching to pyrite oxidation was investigated by analyzing the differences of residue morphologies, leaching rates, surface products, and microbial consortia under different conditions in this study. This was achieved by novel equipment that can control the redox potential of the solution and isolate pyrite from microbial contact oxidation. The morphology of residues showed that the corrosions were a little bit severer in the presence of attached microbes under 750 mV and 850 mV (vs. SHE). At 650 mV, the oxidation of pyrite was undetectable even in the presence of attached microbes. The pyrite dissolution rate was higher with attached microbes than that without attached microbes at 750 mV and 850 mV. The elemental sulfur on the surface of pyrite residues with sessile microorganisms was much less than that without attached microbes at 750 mV and 850 mV, showing that sessile acidophiles may accelerate pyrite leaching by reducing the elemental sulfur inhibition. Many more sulfur-oxidizers were found in the sessile microbial consortium which also supported the idea. The results suggest that the microbial “contact leaching” to pyrite oxidation is limited and relies on the elimination of elemental sulfur passivation by attached sulfur-oxidizing microbes rather than the contact oxidation by EPS-Fe.

scholarly journals Thauera aminoaromatica MZ1T Identified as a Polyhydroxyalkanoate-Producing Bacterium within a Mixed Microbial Consortium

2020 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Dana I. Colpa ◽  
Wen Zhou ◽  
Jan Pier Wempe ◽  
Jelmer Tamis ◽  
Marc C. A. Stuart ◽  
...  
Keyword(s):  
Pure Culture ◽  
Pilot Plant ◽  
Fossil Fuel ◽  
Microbial Consortium ◽  
Population Analysis ◽  
C:N Ratio ◽  
Microbial Consortia ◽  
Waste Streams ◽  
Reserve Material ◽  
Working Volume

Polyhydroxyalkanoates (PHAs) form a highly promising class of bioplastics for the transition from fossil fuel-based plastics to bio-renewable and biodegradable plastics. Mixed microbial consortia (MMC) are known to be able to produce PHAs from organic waste streams. Knowledge of key-microbes and their characteristics in PHA-producing consortia is necessary for further process optimization and direction towards synthesis of specific types of PHAs. In this study, a PHA-producing mixed microbial consortium (MMC) from an industrial pilot plant was characterized and further enriched on acetate in a laboratory-scale selector with a working volume of 5 L. 16S-rDNA microbiological population analysis of both the industrial pilot plant and the 5 L selector revealed that the most dominant species within the population is Thauera aminoaromatica MZ1T, a Gram-negative beta-proteobacterium belonging to the order of the Rhodocyclales. The relative abundance of this Thauera species increased from 24 to 40% after two months of enrichment in the selector-system, indicating a competitive advantage, possibly due to the storage of a reserve material such as PHA. First experiments with T. aminoaromatica MZ1T showed multiple intracellular granules when grown in pure culture on a growth medium with a C:N ratio of 10:1 and acetate as a carbon source. Nuclear magnetic resonance (NMR) analyses upon extraction of PHA from the pure culture confirmed polyhydroxybutyrate production by T. aminoaromatica MZ1T.

Proteolytic activity of two commercial proteinases from Aspergillus oryzae and Bacillus subtilis on ovine and bovine caseins

1991 ◽  
Vol 58 (4) ◽  
pp. 461-467 ◽  
Author(s):  
Rosina López-Fandiño ◽  
Mercedes Ramos ◽  
Estrella Fernández-García ◽  
Agustin Olano
Keyword(s):  
Bacillus Subtilis ◽  
Electrophoretic Mobility ◽  
Proteolytic Activity ◽  
Aspergillus Oryzae ◽  
Electrophoretic Analysis ◽  
Breakdown Product ◽  
Commercial Enzymes ◽  
Fungal Protease ◽  
Hydrolysis Of

SummaryElectrophoretic analysis of the action of two commercial enzymes, Neutrase 0·5 and MKC Fungal Protease, on whole casein and αs-, β- and κ-caseins from cows' and ewes' milk showed that Neutrase 0·5 chiefly degraded β-casein, giving rise to peptides soluble at pH 4·6 detectable by PAGE. In contrast, although MKC Fungal Protease caused intense hydrolysis of bovine β-casein, in ovine casein it resulted in more active degradation of αs- than β-casein. The latter enzyme did not produce peptides soluble at pH 4·6 detectable by PAGE. Both enzymes degraded κ-casein, yielding a breakdown product that exhibited an electrophoretic mobility similar to that of the breakdown product produced by the action of commercial rennet.

scholarly journals The effect of heavy metals on thiocyanate biodegradation by an autotrophic microbial consortium enriched from mine tailings

2020 ◽  
Author(s):  
Farhad Shafiei ◽  
Mathew P. Watts ◽  
Lukas Pajank ◽  
John W. Moreau
Keyword(s):  
Heavy Metals ◽  
Mine Tailings ◽  
Energy Demand ◽  
High Efficiency ◽  
Microbial Consortium ◽  
Bacterial Consortium ◽  
Process Efficiency ◽  
Microbial Consortia ◽  
List Type ◽  
Gold Mine Tailings

AbstractBioremediation systems represent an environmentally sustainable approach to degrading industrially-generated thiocyanate (SCN-), with low energy demand and operational costs, and high efficiency and substrate specificity. However, heavy metals present in mine tailings effluent may hamper process efficiency by poisoning thiocyanate-degrading microbial consortia. Here we experimentally tested the tolerance of an autotrophic SCN--degrading bacterial consortium enriched from gold mine tailings for Zn, Cu, Ni, Cr, and As. All of the selected metals inhibited SCN- biodegradation to different extents, depending on concentration. At pH of 7.8 and 30°C, complete inhibition of SCN- biodegradation by Zn, Cu, Ni, and Cr occurred at 20, 5, 10, and 6 mg L-1, respectively. Lower concentrations of these metals decreased the rate of SCN- biodegradation, with relatively long lag times. Interestingly, the microbial consortium tolerated As even at 500 mg L-1, although both the rate and extent of SCN- biodegradation were affected. This study highlights the importance of considering metal co-contamination in bioreactor design and operation for SCN- bioremediation at mine sites.Key pointsBoth the efficiency and rate of SCN- biodegradation were inhibited by heavy metals, to different degrees depending on type and concentration of metalThe autotrophic microbial consortium was capable of tolerating high levels of As

scholarly journals A Unique Sulfotransferase-Involving Strigolactone Biosynthetic Route in Sorghum

2021 ◽  
Vol 12 ◽  
Author(s):  
Sheng Wu ◽  
Yanran Li
Keyword(s):  
Cytochrome P450 ◽  
Biochemical Characterization ◽  
Microbial Consortium ◽  
Microbial Consortia ◽  
Synthetic Route ◽  
Germination Stimulant ◽  
Catalytic Function

LOW GERMINATION STIMULANT 1 (LGS1) plays an important role in strigolactones (SLs) biosynthesis and Striga resistance in sorghum, but the catalytic function remains unclear. Using the recently developed SL-producing microbial consortia, we examined the activities of sorghum MORE AXILLARY GROWTH1 (MAX1) analogs and LGS1. Surprisingly, SbMAX1a (cytochrome P450 711A enzyme in sorghum) synthesized 18-hydroxy-carlactonoic acid (18-hydroxy-CLA) directly from carlactone (CL) through four-step oxidations. The further oxidated product orobanchol (OB) was also detected in the microbial consortium. Further addition of LGS1 led to the synthesis of both 5-deoxystrigol (5DS) and 4-deoxyorobanchol (4DO). Further biochemical characterization found that LGS1 functions after SbMAX1a by converting 18-hydroxy-CLA to 5DS and 4DO possibly through a sulfonation-mediated pathway. The unique functions of SbMAX1 and LGS1 imply a previously unknown synthetic route toward SLs.

scholarly journals Enrichment and Analysis of Stable 1,4-dioxane-Degrading Microbial Consortia Consisting of Novel Dioxane-Degraders

2019 ◽  
Vol 8 (1) ◽  
pp. 50 ◽  
Author(s):  
Tanmoy Roy Tusher ◽  
Takuya Shimizu ◽  
Chihiro Inoue ◽  
Mei-Fang Chien
Keyword(s):  
Ribosomal Rna ◽  
Industrial Wastewater ◽  
Microbial Consortium ◽  
Mineral Salt Medium ◽  
Intergenic Spacer ◽  
Mineral Salt ◽  
Microbial Consortia ◽  
Salt Medium ◽  
Bacterial Strains ◽  
Water Contaminant

Biodegradation of 1,4-dioxane, a water contaminant of emerging concern, has drawn substantial attention over the last two decades. A number of dioxane-degraders have been identified, though many of them are unable to metabolically utilize 1,4-dioxane. Moreover, it is considered more preferable to use microbial consortia rather than the pure strains, especially in conventional bioreactors for industrial wastewater treatment. In the present study, a stable 1,4-dioxane-degrading microbial consortium was enriched, namely 112, from industrial wastewater by nitrate mineral salt medium (NMSM). The consortium 112 is capable of utilizing 1,4-dioxane as a sole carbon and energy source, and can completely degrade 1,4-dioxane up to 100 mg/L. From the consortium 112, two 1,4-dioxane-degrading bacterial strains were isolated and identified, in which the Variovorax sp. TS13 was found to be a novel 1,4-dioxane-degrader that can utilize 100 mg/L of 1,4-dioxane. The efficacy of the consortium 112 was increased significantly when we cultured the consortium with mineral salt medium (MSM). The new consortium, N112, could utilize 1,4-dioxane at a rate of 1.67 mg/L·h. The results of the ribosomal RNA intergenic spacer analysis (RISA) depicted that changes in the microbial community structure of consortium 112 was the reason behind the improved degradation efficiency of consortium N112, which was exhibited as a stable and effective microbial consortium with a high potential for bioremediation of the dioxane-impacted sites and contaminated industrial wastewater.

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