scholarly journals Biotransformations of HBCDs by Rhodococcus Strain Stu-38 and Identification of Transformation Products

2021 ◽  
Author(s):  
Fei Yu ◽  
Wenqi Luo ◽  
Yuyang Li ◽  
Shanshan Meng ◽  
Xianbin Lin ◽  
...  
Keyword(s):  
Carbon Source ◽  
Flame Retardants ◽  
Mineral Salt Medium ◽  
Removal Rate ◽  
Transformation Products ◽  
Mangrove Sediment ◽  
Transformation Rate ◽  
Salt Medium ◽  
Cultural Media ◽  
Rhodococcus Strain

Abstract 1, 2, 5, 6, 9, 10-Hexabromocyclododecanes (HBCDs) are new brominated flame retardants causing serious environmental pollution. Dozens of degradative bacteria have been found with capacity to transform HBCDs. In the present study, an aerobic functional bacterium Rhodococcus strain stu-38 was isolated from enriched culture of mangrove sediment using HBCDs as carbon source. This strain could stereoselectively transform HBCDs, the removal rate was α-＞γ-＞β-HBCD in the mineral salt medium, but was β-＞α- and γ-HBCD in the growth medium, and it selectively transformed γ- HBCD in the seawater. Transformation rate of strain stu-38 was lower than other functional strains, however, seven potential debrominated products of HBCDs were identified by using GC-MS. These debrominated products, included dibromocyclododecadiene, bromocyclododecadienol and bromocyclododecatriene were formed through reductive debromination, hydrolytic debromination and dehydrobromination. Overall, Rhodococcus sp. stu-38 diastereoisomer-specifically transformed HBCDs to various debrominated products in the different cultural media, which highlighted the complicated stereoselective biotransformation of HBCDs.

scholarly journals Low-Density Polyethylene Film Biodegradation Potential by Fungal Species from Thailand

2021 ◽  
Vol 7 (8) ◽  
pp. 594
Author(s):  
Sarunpron Khruengsai ◽  
Teerapong Sripahco ◽  
Patcharee Pripdeevech
Keyword(s):  
Carbon Source ◽  
Sole Carbon Source ◽  
Mineral Salt Medium ◽  
Plastic Waste ◽  
Mineral Salt ◽  
Alternative Methods ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Salt Medium ◽  
Ldpe Film

Accumulated plastic waste in the environment is a serious problem that poses an ecological threat. Plastic waste has been reduced by initiating and applying different alternative methods from several perspectives, including fungal treatment. Biodegradation of 30 fungi from Thailand were screened in mineral salt medium agar containing low-density polyethylene (LDPE) films. Diaporthe italiana, Thyrostroma jaczewskii, Collectotrichum fructicola, and Stagonosporopsis citrulli were found to grow significantly by culturing with LDPE film as the only sole carbon source compared to those obtained from Aspergillus niger. These fungi were further cultured in mineral salt medium broth containing LDPE film as the sole carbon source for 90 days. The biodegradation ability of these fungi was evaluated from the amount of CO2 and enzyme production. Different amounts of CO2 were released from D. italiana, T. jaczewskii, C. fructicola, S. citrulli, and A. niger culturing with LDPE film, ranging from 0.45 to 1.45, 0.36 to 1.22, 0.45 to 1.45, 0.33 to 1.26, and 0.37 to 1.27 g/L, respectively. These fungi were able to secrete a large amount of laccase enzyme compared to manganese peroxidase, and lignin peroxidase enzymes detected under the same conditions. The degradation of LDPE films by culturing with these fungi was further determined. LDPE films cultured with D. italiana, T. jaczewskii, C. fructicola, S. citrulli, and A. niger showed weight loss of 43.90%, 46.34%, 48.78%, 45.12%, and 28.78%, respectively. The tensile strength of LDPE films cultured with D. italiana, T. jaczewskii, C. fructicola, S. citrulli, and A. niger also reduced significantly by 1.56, 1.78, 0.43, 1.86, and 3.34 MPa, respectively. The results from Fourier transform infrared spectroscopy (FTIR) reveal an increasing carbonyl index in LDPE films culturing with these fungi, especially C. fructicola. Analysis of LDPE films using scanning electron microscopy (SEM) confirmed the biodegradation by the presence of morphological changes such as cracks, scions, and holes on the surface of the film. The volatile organic compounds (VOCs) emitted from LDPE films cultured with these fungi were analyzed by gas chromatography-mass spectrometry (GC-MS). VOCs such as 1,3-dimethoxy-benzene, 1,3-dimethoxy-5-(1-methylethyl)-benzene, and 1,1-dimethoxy-decane were detected among these fungi. Overall, these fungi have the ability to break down and consume the LDPE film. The fungus C. fructicola is a promising resource for the biodegradation of LDPE which may be further applied in plastic degradation systems based on fungi.

scholarly journals Wild type Bacillus subtilis treated with ethyl methyl sulphonate produced catabolite insensitive mutants with improved cellulase production

2021 ◽  
Author(s):  
Oladipo Olaniyi
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Enzyme Production ◽  
Cellulase Activity ◽  
Cellulase Production ◽  
Minimal Salt Medium ◽  
Salt Medium ◽  
Production Medium ◽  
Wild Type ◽  
Ethyl Methyl

Abstract The goal of this present investigation was to mutagenize Bacillus subtilis with Ethyl Methyl Sulphonate (EMS), screen the mutants for cellulase production and evaluate the influence of different glucose concentrations on their cellulase production potentials. The wild type B. subtilis was treated with 20, 40, 60 and 80 µl of EMS and the mutants generated were screened for cellulase production in minimal salt medium containing carboxylmethylcellulose (CMC) as the carbon source. Quantitatively, cellulase activity and protein contents were determined by dinitrosalicylic acid and Lowry methods respectively. Seven mutants were developed from each of the EMS concentration bringing the total to twenty-eight from all the concentrations. Approximately 14 and 57% of the mutants developed from 40 and 60µl of EMS had higher cellulase activities than the wild type, while none of the mutants developed from 20 and 80 µl of EMS had better activities than the wild type. The supplementation of 0.2, 0.5, 1.0 and 1.5% glucose in enzyme production medium caused approximately 100, 14, 29 and 14% cellulase repression respectively in the mutants developed from 60µl EMS. Mutants MSSS02 and MSSS05 were considered as catabolite insensitive mutants because their cellulase production were enhanced in comparison to wild type.

Improvment of nitrogen and phosphorus removal in the anaerobic-oxic-anoxic-OXIC (AOAO) process by stepwise feeding

2000 ◽  
Vol 42 (3-4) ◽  
pp. 89-94 ◽  
Author(s):  
H.Y. Chang ◽  
C.F. Ouyang
Keyword(s):  
Carbon Source ◽  
Phosphorus Removal ◽  
Removal Rate ◽  
Feeding Strategy ◽  
Synthetic Wastewater ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Kjeldahl Nitrogen ◽  
P Removal

This investigation incorporated a stepwise feeding strategy into the biological process containing anaerobic/oxide/anoxic/oxide (AOAO) stages to enhance nitrogen and phosphorus removal efficiencies. Synthetic wastewater was fed into the experimental reactors during the anaerobic and anoxic stages and the substrates/nutrients were successfully consumed without recycling either nitrified effluent or external carbon source. An intrinsic sufficient carbon source developed during the anoxic stage and caused the NOx (NO2-N+NO3-N) concentration to be reduced from 11.85mg/l to 5.65mg/l. The total Kjeldahl nitrogen (TKN) removal rate was between 81.81%∼93.96% and the PO4-P removal ratio ranged from 93%∼100%. The substrate fed into the anaerobic with a Q1 flow rate and a Q2 into the anoxic reactor. The three difference experiments contained within this study produced Q1/Q2 that varied from 7/3, 8/2, and 9/1. The AOAO process saved nearly one-third of the energy compared with typical biological nutrient removal (BNR) system A2O processes.

Metabolism of a monoterpene alcohol, linalool, by a soil pseudomonad

1977 ◽  
Vol 23 (3) ◽  
pp. 230-239 ◽  
Author(s):  
K. M. Madyastha ◽  
P. K. Bhattacharyya ◽  
C. S. Vaidyanathan
Keyword(s):  
Mineral Salt Medium ◽  
Enrichment Culture ◽  
Sole Source ◽  
Mineral Salt ◽  
Salt Medium ◽  
Culture Techniques ◽  
Unsaturated Lactone ◽  
Linalool Oxide

A microorganism of the genus Pseudomonas has been isolated from the soil by enrichment culture techniques with linalool(I) as the sole source of carbon and energy. The organism is also capable of utilizing limonene, citronellol, and geraniol as substrates but fails to grow on citral, citranellal, and 1,8-cineole. Fermentation of linalool by this bacterium in a mineral salt medium results in the formation of 10-hydroxylinalool(II), 10-carboxylinalool(III), oleuropeic acid(IX), 2-vinyl-2-methyl-5-hydroxyisopropyl-tetrahydrofuran(linalool oxide, V), 2-vinyl-2-methyl-tetrahydrofuran-5-one(unsaturated lactone, VI), and few unidentified minor metabolites. Probable pathways for the biodegradation of linalool are presented.

scholarly journals Methane Emissions Driven by Adding a Gradient of Ethanol as Carbon Source in Integrated Vertical-Flow Constructed Wetlands

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1086
Author(s):  
Xiaoling Liu ◽  
Jingting Wang ◽  
Xiaoying Fu ◽  
Hongbing Luo ◽  
Bruce C. Anderson ◽  
...  
Keyword(s):  
Carbon Source ◽  
Constructed Wetlands ◽  
Control Experiment ◽  
Ethanol Concentration ◽  
Removal Rate ◽  
Carbon Sources ◽  
Vertical Flow ◽  
Emission Flux ◽  
Rate Range ◽  
External Carbon Source

This work aims to investigate the methane emissions from integrated vertical-flow constructed wetlands (IVCWs) when ethanol is added as an external carbon source. In this study, a gradient of ethanol (0, 2, 4, 8, 16 and 32 mmol/L) was added as the carbon source in an IVCW planted with Cyperus alternifolius L. The results showed that the methane emission flux at an ethanol concentration of 32 mmol/L was 32.34 g CH4 m−2 day−1 less than that of the control experiment (0 mmol/L) and that the methane emission flux at an ethanol concentration of 16 mmol/L was 5.53 g CH4 m−2 day−1 less than that at 0 mmol/L. In addition, variations in the water quality driven by the different ethanol concentrations were found, with a redox potential range of −64 mV to +30 mV, a pH range of 6.6–6.9, a chemical oxygen demand (COD) removal rate range of 41% to 78%, and an ammonia nitrogen removal rate range of 59% to 82% after the ethanol addition. With the average CH4-C/TOC (%) value of 35% driven by ethanol, it will be beneficial to understand that CH4-C/TOC can be considered an ecological indicator of anthropogenic methanogenesis from treatment wetlands when driven by carbon sources or carbon loading. It can be concluded that adding ethanol as an external carbon source can not only meet the water quality demand of the IVCW treatment system but also stimulate and increase the average CH4 emissions from IVCWs by 23% compared with the control experiment. This finding indicates that an external carbon source can stimulate more CH4 emissions from IVCWs and shows the importance of carbon sources during sewage treatment processes when considering greenhouse emissions from treated wetlands.

Paraffin Oil-Enhanced Biodegradation of Naphthalene by Hydrogenophaga palleronii LHJ38

2010 ◽  
Vol 113-116 ◽  
pp. 243-249 ◽  
Author(s):  
Jia Ying Xin ◽  
Yan Wang ◽  
Ying Xin Zhang ◽  
Chun Gu Xia
Keyword(s):  
Energy Source ◽  
Aqueous Phase ◽  
Degradation Rate ◽  
Mineral Salt Medium ◽  
Dry Weight ◽  
Salt Medium ◽  
Optimum Conditions ◽  
Naphthalene Degradation ◽  
Paraffin Oil ◽  
Enhanced Biodegradation

Hydrogenophaga palleronii LHJ38 can grow on naphthalene as sole carbon and energy source. The growth and naphthalene degradation curve of the strain were determined in biphase and monophase system respectively. The growth and naphthalene degradation capacity of cells obtained from oil phase and aqueous phase were compared carefully. The maximum biomass of 4.248g/L was obtained after cultivating 72h under the optimum conditions of 30 mL paraffin oil and 2g naphthalene in 1L mineral salt medium. In the biphase system, the naphthalene degradation capacity of Hydrogenophaga palleronii LHJ38 was higher more than 2 times than that in the monophase system. The naphthalene (2g/L) can be degraded completely in 132h when the concentration of cell was 2 mg dry weight cell/mL. The naphthalene degradation rate of cells obtained from oil phase was 2.7 fold as fast as that of cells obtained from aqueous phase.

Granular activated algae for wastewater treatment

2015 ◽  
Vol 71 (6) ◽  
pp. 832-839 ◽  
Author(s):  
O. Tiron ◽  
C. Bumbac ◽  
I. V. Patroescu ◽  
V. R. Badescu ◽  
C. Postolache
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Transformation Rate ◽  
Batch Mode ◽  
Promising Alternative ◽  
Ph Variation ◽  
Microalgae Harvesting ◽  
Cost Efficient

The study used activated algae granules for low-strength wastewater treatment in sequential batch mode. Each treatment cycle was conducted within 24 h in a bioreactor exposed to 235 μmol/m2/s light intensity. Wastewater treatment was performed mostly in aerobic conditions, oxygen being provided by microalgae. High removal efficiency of chemical oxygen demand (COD) was achieved (86–98%) in the first hours of the reaction phase, during which the indicator's removal rate was 17.4 ± 3.9 mg O2/g h; NH4+ was removed during organic matter degradation processes with a rate of 1.8 ± 0.6 mg/g h. After almost complete COD removal, the NH4+ remaining in the liquor was removed through nitrification processes promoted by the increase of the liquor's oxygen saturation (O2%), the transformation rate of NH4+ into NO3− increasing from 0.14 ± 0.05 to 1.5 ± 0.4 mg NH4+/g h, along with an O2% increase. A wide removal efficiency was achieved in the case of PO43– (11–85%), with the indicator's removal rate being 1.3 ± 0.7 mg/g h. In the provided optimum conditions, the occurrence of the denitrifying activity was also noticed. A large pH variation was registered (5–8.5) during treatment cycles. The granular activated algae system proved to be a promising alternative for wastewater treatment as it also sustains cost-efficient microalgae harvesting, with microalgae recovery efficiency ranging between 99.85 and 99.99% after granules settling with a velocity of 19 ± 3.6 m/h.

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