Abiotic and Biotic Degradation of Oxo-Biodegradable Plastic Bags by Pleurotus ostreatus

In this study, we evaluated the growth of Pleurotus ostreatus PLO6 using oxo-biodegradable plastics as a carbon and energy source. Oxo-biodegradable polymers contain pro-oxidants that accelerate their physical and biological degradation. These polymers were developed to decrease the accumulation of plastic waste in landfills. To study the degradation of the plastic polymers, oxo-biodegradable plastic bags were exposed to sunlight for up to 120 days, and fragments of these bags were used as substrates for P. ostreatus. We observed that physical treatment alone was not sufficient to initiate degradation. Instead, mechanical modifications and reduced titanium oxide (TiO₂) concentrations caused by sunlight exposure triggered microbial degradation. The low specificity of lignocellulolytic enzymes and presence of endomycotic nitrogen-fixing microorganisms were also contributing factors in this process.     

Promising cellulolytic fungi isolates for rice straw degradation

The objective of this study was to evaluate the potential of eight fungal isolates obtained from soils in rice crops for straw degradation in situ. From the initial eight isolates, Pleurotus ostreatus T1.1 and Penicillium sp. HC1 were selected for further characterization based on qualitative cellulolytic enzyme production and capacity to use rice straw as a sole carbon source. Subsequently, cellulolytic, xylanolytic, and lignolytic (Pleurotus ostreatus) activity on carboxymethyl cellulose, oat xylan, and rice straw with different nitrogen sources was evaluated. From the results obtained it was concluded both isolates are capable to produce enzymes necessary for rice straw degradation. However, their production is dependent upon carbon and nitrogen source. Last, it was established that Pleurotus ostreatus T1.1 and Penicillium sp. HC1 capability to colonize and mineralize rice straw, in mono-and co-culture, without affecting nitrogen soil content.     

Olive mill wastewater remediation by means of Pleurotus ostreatus

Results of a research program on raw olive-mill wastewater (OMW) bioremediation are presented. Bioremediation experiments have been carried out both in an airlift bioreactor and in aerated flasks, using Pleurotus ostreatus. The process was investigated under controlled non-sterile operating conditions, representative of industrial operation. Growth of P. ostreatus as well as polyphenols conversion were assessed. OMW bioconversion was characterized in terms of total organic carbon, polyphenols concentration, phenol oxidase activity, extent of decolourization and pH as a function of time. Results demonstrate that: P. ostreatus effectively grows on raw OMW; polyphenols abatement is controlled by the availability of nutrients and can be as large as 95%; bioconversion of non-sterilized OMW does not result into appreciable decolourization of the liquid medium. The use of an internal loop airlift bioreactor as a candidate for the full-scale implementation of an OMW aerobic bioremediation process is demonstrated.     

Fungal solid state fermentation on agro-industrial wastes for acid wastewater decolorization in a continuous flow packed-bed bioreactor

This study was aimed at developing a process of solid state fermentation (SSF) with the fungi Pleurotus ostreatus and Trametes versicolor on apple processing residues for wastewater decolorization. Both fungi were able to colonize apple residues without any addition of nutrients, material support or water. P. ostreatus produced the highest levels of laccases (up to 9 U g⁻¹ of dry matter) and xylanases (up to 80 U g⁻¹ of dry matter). A repeated batch decolorization experiment was set up with apple residues colonized by P. ostreatus, achieving 50% decolorization and 100% detoxification after 24 h, and, adding fresh wastewater every 24 h, a constant decolorization of 50% was measured for at least 1 month. A continuous decolorization experiment was set up by a packed-bed reactor based on colonized apple residues achieving a performance of 100 mg dye L⁻¹ day⁻¹ at a retention time of 50 h.     

Maintenance of phosphorus removal in an EBPR system under permanent aerobic conditions using propionate

Enhanced biological phosphorus removal (EBPR) is an efficient and sustainable technology to remove phosphorus from wastewater preventing eutrophication in natural waters. It is widely accepted that EBPR requires an optimal anaerobic hydraulic retention time to obtain stable P-removal from wastewater. Thus, it is suggested that deterioration of the EBPR efficiency regularly observed in full-scale wastewater treatment plants (WWTPs) is normally caused by an excessive aeration of activated sludge that increments the amount of oxygen recycled to the anaerobic reactor and consequently, the anaerobic conditions are not totally preserved. Furthermore, it has been reported a progressive decrease in P-removal capacity in an EBPR lab-scale system enriched with acetate as the sole carbon source under permanent aerobic conditions. Hence, to evaluate the stability of P-removal with a different carbon source, an EBPR-SBR was operated with propionate under permanent aerobic conditions. As a result, net P-removal was successfully accomplished in the SBR without any anaerobic phase during 46 days of aerobic operation. Moreover, the system was shifted after this period to the standard anaerobic–aerobic conditions and reliable P-removal was maintained. FISH (fluorescence in situ hybridisation) analysis showed a significant presence of Accumulibacter (70, 50 and 72%, in different periods) and the absence of Competibacter. The results indicate that using propionate as carbon source it is possible to maintain in a long term an enriched culture of phosphorus accumulating organisms (PAO) able to remove phosphorus under permanent aerobic conditions.     

Bio-remediation of colored industrial wastewaters by the white-rot fungi Phanerochaete chrysosporium and Pleurotus ostreatus and their enzymes

The effect of Phanerochaete chrysosporium and Pleurotus ostreatus whole cells and their ligninolytic enzymes on models of colored industrial wastewaters was evaluated. Models of acid, direct and reactive dye wastewaters from textile industry have been defined on the basis of discharged amounts, economic relevance and representativeness of chemical structures of the contained dyes. Phanerochaete chrysosporium provided an effective decolourization of direct dye wastewater model, reaching about 45% decolourization in only 1 day of treatment, and about 90% decolourization within 7 days, whilst P. ostreatus was able to decolorize and detoxify acid dye wastewater model providing 40% decolourization in only 1 day, and 60% in 7 days. P. ostreatus growth conditions that induce laccase production (up to 130,000 U/l) were identified, and extra-cellular enzyme mixtures, with known laccase isoenzyme composition, were produced and used in wastewater models decolourization. The mixtures decolorized and detoxified the acid dye wastewater model, suggesting laccases as the main agents of wastewater decolourization by P. ostreatus. A laccase mixture was immobilized by entrapment in Cu-alginate beads, and the immobilized enzymes were shown to be effective in batch decolourization, even after 15 stepwise additions of dye for a total exposure of about 1 month.     

Preliminary evaluation of Pleurotus ostreatus for the removal of selected pharmaceuticals from hospital wastewater

The fungus Pleurotus ostreatus was investigated to assess its ability to remove diclofenac, ketoprofen, and atenolol spiked at 10 mg/L each one in hospital wastewater. The degradation test was carried out in a fluidized bed bioreactor testing both the batch and the continuous mode (hydraulic retention time in the range 1.63–3 days). In batch mode, diclofenac disappeared in less than 24 h, ketoprofen was degraded up to almost 50% in 5 days while atenolol was not removed. In continuous mode, diclofenac and ketoprofen removals were about 100% and 70% respectively; atenolol degradation was negligible during the first 20 days but it increased up to 60% after a peak of laccase production and notable biomass growth. In order to identify the enzymatic system involved, further experiments were carried out in flasks. Purified laccase completely transformed atenolol and diclofenac in less than 5 h, but not ketoprofen. In vivo experiments suggested that cytochrome P450 could be involved in diclofenac and ketoprofen degradation, while partial correlation studies confirmed the role of laccase in atenolol and diclofenac degradation. Two intermediates of diclofenac and ketoprofen were detected by nuclear magnetic resonance. Moreover P. ostreatus was able to reduce chemical oxygen demand of the hospital wastewater which is an important advantage comparing to other fungi in order to develop a wastewater treatment process. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1529–1537, 2017     

Enzymatic extract containing lignin peroxidase immobilized on carbon nanotubes: Potential biocatalyst in dye decolourization

The majority of the textile dyes are harmful to the environment and potentially carcinogenic. Among strategies for their exclusion, the treatment of dye contaminated wastewater with fungal extract, containing lignin peroxidase (LiP), may be useful. Two fungi isolates, Pleurotus ostreatus (PLO9) and Ganoderma lucidum (GRM117), produced the enzymatic extract by fermentation in the lignocellulosic residue, Jatropha curcas seed cake. The extracts from PLO9 and GRM117 were immobilized on carbon nanotubes and showed an increase of 18 and 27-fold of LiP specific activity compared to the free enzyme. Also, LiP from both fungi extracts showed higher Vmax and lower Km values. Only the immobilized extracts could be efficiently reused in the dye decolourization, contrary, the carbon nanotubes became saturated and they should be discarded over time. This device may offer a final biocatalyst with higher catalytic efficiency and capability to be reused in the dye decolourization process.     

糙皮侧耳和鞘脂菌NS7对多环芳烃污染土壤的生物强化与协同作用

【背景】真菌和细菌被认为在多环芳烃污染土壤生物修复过程中发挥协同作用,目前在真实土壤体系中开展真菌-细菌协同降解研究较少。【目的】研究真菌和细菌对不同种类多环芳烃降解的差异及对蒽和苯并[a]蒽的生物强化与协同作用。【方法】选用多环芳烃降解真菌和细菌各一株,在液体纯培养体系下分析它们对不同种类多环芳烃降解的差异,在土壤体系中采用放射性同位素示踪技术研究2种微生物对蒽和苯并[a]蒽的生物强化与协同作用。【结果】供试细菌鞘脂菌NS7能够很好地降解低环种类多环芳烃,以蒽作为唯一碳源时可以将其完全降解,在复合污染条件下对菲、蒽、荧蒽、芘等降解效果突出(>90%),对苯并[a]芘降解效果较差(9.76%)。相比而言,供试真菌糙皮侧耳菌对苯并[a]芘具有更好的降解效果(21.18%),对低环多环芳烃降解效果明显不如降解菌NS7。在自然土壤中,蒽和苯并[a]蒽具有明显不同的矿化效率,分别为18.61%和4.28%,在蒽污染土壤中加入鞘脂菌NS7并未显著提高蒽的矿化率(P>0.05),相比而言,苯并[a]蒽污染土壤中加入糙皮侧耳显著提高了污染物矿化效率(2.24倍),表明真菌和细菌在土壤环境...     

Biodegradation of aflatoxin B1 in contaminated rice straw by Pleurotus ostreatus MTCC 142 and Pleurotus ostreatus GHBBF10 in the presence of metal salts and surfactants

Aflatoxin B1 (AFB1) is a highly toxic fungal metabolite having carcinogenic, mutagenic and teratogenic effects on human and animal health. Accidental feeding of aflatoxin-contaminated rice straw may be detrimental for ruminant livestock and can lead to transmission of this toxin or its metabolites into the milk of dairy cattle. White-rot basidiomycetous fungus Pleurotus ostreatus produces ligninolytic enzymes like laccase and manganese peroxidase (MnP). These extracellular enzymes have been reported to degrade many environmentally hazardous compounds. The present study examines the ability of P. ostreatus strains to degrade AFB1 in rice straw in the presence of metal salts and surfactants. Laccase and MnP activities were determined spectrophotometrically. The efficiency of AFB1 degradation was evaluated by high performance liquid chromatography. Highest degradation was recorded for both P. ostreatus MTCC 142 (89.14 %) and P. ostreatus GHBBF10 (91.76 %) at 0.5 µg mL^?1 initial concentration of AFB1. Enhanced degradation was noted for P. ostreatus MTCC 142 in the presence of Cu²⁺ and Triton X-100, at toxin concentration of 5 µg mL^?1. P. ostreatus GHBBF10 showed highest degradation in the presence of Zn²⁺ and Tween 80. Liquid chromatography-mass spectrometric analysis revealed the formation of hydrated, decarbonylated and O-dealkylated products. The present findings suggested that supplementation of AFB1-contaminated rice straw by certain metal salts and surfactants can improve the enzymatic degradation of this mycotoxin by P. ostreatus strains.     

Degradation of Green Polyethylene by Pleurotus ostreatus

We studied the biodegradation of green polyethylene (GP) by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers.     

Fungal wood decay in the presence of fly ash as indicated by gravimetrics and by extractability of low molecular weight volatile organic acids

A mycoremediation system of wood substrate and fungal inoculum was established on an organically poor fly ash deposit at the ?o?tanj Thermal Power Plant, Slovenia. A mini-block method with beech wood samples was used to select a suitable fungal isolate for inoculation into the mycoremediation system. Pleurotus ostreatus ZIM 76 proved to be the most appropriate for further tests. Compared to the mass loss in a non-contaminated medium, wood degradation with the selected fungal isolate was reduced by 51% on wood substrate contaminated with 17% (w/w) fly ash. The deterioration processes of wood chips on inoculated and non-inoculated experimental plots were studied by ionic chromatographic analyses of volatile organic acids in water extracts. The presence of P. ostreatus did not influence the concentrations of acetic and formic acids in water extracts from wood chips collected at experimental plots in different intervals from May 2006 to November 2007 comparing inoculated vs. non-inoculated plots.     

Comparative analysis of the antibodies against capsular polysaccharides of Escherichia coli k-92 and k-235: An immunochemical method for the identification of polysialic acids

• 1.1. The antibodies produced against the capsular poly-N-acetylneuraminic acid (poly-Neu5Ac) of E. coliK-92 (α 2-8-, α 2-9-linked) were 100-fold less sensitive than those obtained against E. coli K-235 capsular polysaccharide (CP) (α 2-8-linked) and recognized both kinds of polymers to a similar extent.
• 2.2. The partial hydrolysis of each purified polysaccharide revealed that E. coli K-92 CP is more labile at acidic pH than the polymer α 2-8-linked of E. coli K-235.
• 3.3. The antisera against CP from E. coli K-92 bound its own oligomers in which the number of Neu5Ac units was higher than three, whereas they only cross-reacted with the oligomers derived from E. coli K-235 containing a number of residues higher than 12.
• 4.4. The antisera against E. coli K-235 CP that recognized α 2–8 oligomers with a number of Neu5Ac residues higher than 5, also reacted, although very weakly, with those containing α2–8 and α 2–9 linkages in which the carbon length was higher than (Neu5Ac)₃.
• 5.5. Both types of antibodies were also able to recognize the native antigens in living bacteria and could be employed for the recognition of the type of linkage presents in different sialylpolymers.

     

Genome shuffling amplifies the carbon source spectrum and improves arachidonic acid production in Diasporangium sp.

The aim of this study was to develop a new fungal strain that simultaneously amplifies the carbon source spectrum and increases arachidonic acid (AA) productivity using genome shuffling between Diasporangium sp. and inactive Aspergillus niger. Through three rounds of genome shuffling, one of the stable daughter strains (F₁) acquired the ability to produce arachidonic acid and utilize various carbon sources. Compared to the parental Diasporangium sp., which could only use four out of eight carbon sources tested, F₁ could utilize all eight carbon sources. During fermentation with CMC-Na as the carbon source, F₁ was able to obtain 30.16% of lipid effectively whereas the parental Diasporangium sp. was not able to grow at all. When glucose was used as the carbon source, the CMCase activity of F₁ was 879.36 U, 298.23% higher than that of the parental Diasporangium sp. Under optimized fermentation conditions in a 5-L fermentation container, the AA yield of F₁ reached 0.81 g/l, 94.78% higher than that of the parental generation. These results indicate that inter-kingdom genome shuffling can be used successfully in eukaryotic microorganisms and that it can effectively improve the production of desired metabolites within a short period of time. The findings of this study may be useful for extending the application of genome shuffling in eukaryotic microbial breeding.     

Metabolic engineering of Cupriavidus necator H16 for heterotrophic and autotrophic production of 3-hydroxypropionic acid

3-Hydroxypropionate (3-HP) is a versatile compound for chemical synthesis and a potential building block for biodegradable polymers. Cupriavidus necator H16, a facultative chemolithoautotroph, is an attractive production chassis and has been extensively studied as a model organism for biopolymer production. Here, we engineered C. necator H16 for 3-HP biosynthesis from its central metabolism. Wild type C. necator H16 can use 3-HP as a carbon source, a highly undesirable trait for a 3-HP production chassis. However, deletion of its three (methyl-)malonate semialdehyde dehydrogenases (mmsA1, mmsA2 and mmsA3) resulted in a strain that cannot grow on 3-HP as the sole carbon source, and this strain was selected as our production host. A stepwise approach was used to construct pathways for 3-HP production via β-alanine. Two additional gene deletion targets were identified during the pathway construction process. Deletion of the 3-hydroxypropionate dehydrogenase, encoded by hpdH, prevented the re-consumption of the 3-HP produced by our engineered strains, while deletion of gdhA1, annotated as a glutamate dehydrogenase, prevented the utilization of aspartate as a carbon source, one of the key pathway intermediates. The final strain carrying these deletions was able to produce up to 8 mM 3-HP heterotrophically. Furthermore, an engineered strain was able to produce 0.5 mM 3-HP under autotrophic conditions, using CO₂ as sole carbon source. These results form the basis for establishing C. necator H16 as an efficient platform for the production of 3-HP and 3-HP-containing polymers.     

Degradation of lindane and endosulfan by fungi, fungal and bacterial laccases

The ability of two white-rot fungi (Trametes versicolor and Pleurotus ostreatus) and one brown-rot fungus (Gloeophyllum trabeum) to degrade two organochlorine insecticides, lindane and endosulfan, in liquid cultures was studied and dead fungal biomass was examined for adsorption of both insecticides from liquid medium. Lindane and endosulfan were also treated with fungal laccase and bacterial protein CotA, which has laccase activities. The amount of degraded lindane and endosulfan increased with their exposure period in the liquid cultures of both examined white-rot fungi. Endosulfan was transformed to endosulfan sulphate by T. versicolor and P. ostreatus. A small amount of endosulfan ether was also detected and its origin was examined. Degradation of lindane and endosulfan by a brown rot G. trabeum did not occur. Mycelial biomasses of all examined fungi have been found to adsorb lindane and endosulfan and adsorption onto fungal biomass should therefore be considered as a possible mechanism of pollutant removal when fungal degradation potentials are studied. Bacterial protein CotA performed more efficient degradation of lindane and endosulfan than fungal laccase and has shown potential for bioremediation of organic pollutants.     

Effect of different carbon and nitrogen sources on laccase and peroxidases production by selected Pleurotus species

Pleurotus eryngii, P. ostreatus and P. pulmonarius produced laccase (Lac) both under conditions of submerged fermentation (SF) and solid-state fermentation (SSF) with all of the investigated carbon and nitrogen sources. The highest levels of Lac activity were found in P. eryngii, under SF conditions of dry ground mandarine peels and in P. ostreatus, strain No. 493, under SSF conditions of grapevine sawdust.High levels of peroxidases activities were occurred in P. ostreatus, strain No. 494, and P. pulmonarius, under SSF conditions of grapevine sawdust, whereas in SF, these activities were either very low or absent.After purification of extracellular crude enzyme mixture of investigated species and strain which were grown in the medium with the best carbon sources, the Lac activity measurements revealed two peaks in P. eryngii, three peaks in both P. ostreatus strains and three in P. pulmonarius. Results obtained after purification also showed that the levels of phenol red oxidation in absence of external Mn²⁺ were higher than phenol red oxidation levels in presence of external Mn²⁺.In the medium with the best carbon sources (mandarine peels and grapevine sawdust, respectively), both P. eryngii and P. ostreatus, strain No. 493, showed the highest Lac activity with (NH₄)₂SO₄, as a nitrogen source, with a nitrogen concentration of 20 and 30 mM, respectively.In P. ostreatus, strain No. 494, and P. pulmonarius, the best nitrogen sources for peroxidases production were peptone in a concentration of 0.5% and NH₄NO₃ with a nitrogen concentration of 30 mM, respectively.     

Lignocellulose Degradation during Solid-State Fermentation: Pleurotus ostreatus versus Phanerochaete chrysosporium

Lignocellulose degradation and activities related to lignin degradation were studied in the solid-state fermentation of cotton stalks by comparing two white rot fungi, Pleurotus ostreatus and Phanerochaete chrysosporium. P. chrysosporium grew vigorously, resulting in rapid, nonselective degradation of 55% of the organic components of the cotton stalks within 15 days. In contrast, P. ostreatus grew more slowly with obvious selectivity for lignin degradation and resulting in the degradation of only 20% of the organic matter after 30 days of incubation. The kinetics of ¹⁴C-lignin mineralization exhibited similar differences. In cultures of P. chrysosporium, mineralization ceased after 18 days, resulting in the release of 12% of the total radioactivity as ¹⁴CO₂. In P. ostreatus, on the other hand, 17% of the total radioactivity was released in a steady rate throughout a period of 60 days of incubation. Laccase activity was only detected in water extracts of the P. ostreatus fermentation. No lignin peroxidase activity was detected in either the water extract or liquid cultures of this fungus. 2-Keto-4-thiomethyl butyric acid cleavage to ethylene correlated to lignin degradation in both fungi. A study of fungal activity under solid-state conditions, in contrast to those done under defined liquid culture, may help to better understand the mechanisms involved in lignocellulose degradation.     

First evidence of mineralization of petroleum asphaltenes by a strain of Neosartorya fischeri

A fungal strain isolated from a microbial consortium growing in a natural asphalt lake is able to grow in purified asphaltenes as the only source of carbon and energy. The asphaltenes were rigorously purified in order to avoid contamination from other petroleum fractions. In addition, most of petroporphyrins were removed. The 18S rRNA and β‐tubulin genomic sequences, as well as some morphologic characteristics, indicate that the isolate is Neosartorya fischeri. After 11 weeks of growth, the fungus is able to metabolize 15.5% of the asphaltenic carbon, including 13.2% transformed to CO₂. In a medium containing asphaltenes as the sole source of carbon and energy, the fungal isolate produces extracellular laccase activity, which is not detected when the fungus grow in a rich medium. The results obtained in this work clearly demonstrate that there are microorganisms able to metabolize and mineralize asphaltenes, which is considered the most recalcitrant petroleum fraction.     

Depolymerisation and biodegradation of a synthetic tanning agent by activated sludges, the bacteria Arthrobacter globiformis and Comamonas testosteroni, and the fungus Cunninghamella polymorpha

Degradation of a synthetic tanning agent CNSF (a condensation product of 2-naphthalenesulfonic acid (2-NSA) and formaldehyde) by four activated sludges, two previously characterised bacterial strains, Arthrobacter sp. 2AC and Comamonas sp. 4BC, and the fungus Cunninghamella polymorpha, was studied in batch culture at 25°C by determining the changes in the concentrations of CNSF and its component monomers and oligomers (n2–n11). The loss of individual oligomers was correlated with the length of the NSA-CH₂ chain. Approximately 25% of the total CNSF was degraded (i.e. mineralised) by the microbes contained in the four activated sludges and by the two bacterial isolates but with different lag phases and at different overall rates. The decline in CNSF concentration was due almost entirely to the biodegradation of the monomers (34.3% of CNSF) and, in particular, 2-NSA (27% of CNSF). There was no change in the n2–n11 components. The growth of C. polymorpha, on the other hand, arose from extracellular depolymerisation of CNSF oligomers and the biodegradation of the lower molecular mass products. Between 38% and 42% of total CNSF was degraded by C. polymorpha at 25°C. The order of oligomer degradation was inversely related to degree of polymerisation. Eighty percent and 90% of the n4 and n5 and 100% oligomers n6–n11 were degraded after 120h. At a higher temperature (37°C) oligomers n4–n11 were degraded completely after 120h. A combination of biodegradation (75%) and sorption to fungal biomass (25%) accounted for the measured loss of all oligomers from the solution phase. The CNSF degradation rates and the volume of fungal biomass produced (and therefore the extent of biosorption) were dependent on the presence of a second carbon source (both optimum at glucose 5g/l). This is the first report that identifies and distinguishes between depolymerisation, sorption and biodegradation processes in the removal of CNSF and its component oligomers. The use of combinations of the depolymerising fungus C.polymorpha, and the monomer-degrading bacteria, Arthrobacter sp. 2AC and Comamonas sp. 4BC, have potential for wastewater treatment.