Degradation of nicosulfuron by a novel isolated bacterial strain Klebsiella sp. Y1: condition optimization, kinetics and degradation pathway

2016 ◽  
Vol 73 (12) ◽  
pp. 2896-2903 ◽  
Author(s):  
Lin Wang ◽  
Xiaolin Zhang ◽  
Yongmei Li
Keyword(s):  
Response Surface Methodology ◽  
Bacterial Strain ◽  
Degradation Pathway ◽  
Optimal Conditions ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Condition Optimization ◽  
Metabolic Degradation ◽  
Hydrolysis Of ◽  
Optimal Ph

Abstract A novel bacterial strain Klebsiella sp. Y1 was isolated from the soil of a constructed wetland, and it was identified based on the 16S rDNA sequence analysis. The co-metabolic degradation of nicosulfuron with glucose by Klebsiella sp. Y1 was investigated. The response surface methodology analysis indicated that the optimal pH and temperature were 7.0 and 35 °C, respectively, for the degradation of nicosulfuron. Under the optimal conditions, the degradation of nicosulfuron fitted Haldane kinetics model well. The removal of nicosulfuron was triggered by the acidification of glucose, which accelerated the hydrolysis of nicosulfuron. Then, the C–N bond of the sulfonylurea bridge was attacked and cleaved. Finally, the detected intermediate 2-amino-4,6-dimethoxypyrimidine was further biodegraded.

scholarly journals Research on Catalytic Denitrification by Zero-Valent Iron (Fe0) and Pd-Ag Catalyst

2021 ◽  
Author(s):  
Yu Zhou ◽  
Yupan Yun ◽  
Xueyou Wen
Keyword(s):  
Response Surface Methodology ◽  
Catalytic Performance ◽  
Zero Valent Iron ◽  
Optimal Conditions ◽  
Single Factor ◽  
Condition Optimization ◽  
Performance Response ◽  
Real Wastewater ◽  
Ag Catalyst ◽  
Orthogonal Tests

Abstract This study primarily focused on how to effectively remove nitrate by catalytic denitrification through zero-valent iron (Fe0) and Pd-Ag catalyst. In order to get better catalytic performance, response surface methodology (RSM), instead of the single factor experiments and orthogonal tests, was firstly applied to optimize the condition parameters of the catalytic process. Results indicated that RSM is accurate and feasible for the condition optimization of catalytic denitrification. Better catalytic performance (71.6% N2 Selectivity) was obtained under the following conditions: 5.1 pH, 127 min reaction time, 3.2 mass ration (Pd: Ag), and 4.2 g/L Fe0, which was higher than the previous study designed by the single factor experiments (68.1%) and orthogonal tests (68.7%). However, under the optimal conditions, N2 selectivity showed a mild decrease (69.3%), when the real wastewater was used as the influent. Further study revealed that the cations (e.g., K+, Na+, Ca2+, Mg2+, and Al3+) and anions (e.g., Cl-, HCO3-, and SO42-) exist in wastewater may have distinctive influence on N2 selectivity. Finally, the reaction mechanism and kinetic model of catalytic denitrification were further studied.

scholarly journals Biodegradation and metabolic pathway of sulfamethoxazole by Sphingobacterium mizutaii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jinlong Song ◽  
Guijie Hao ◽  
Lu Liu ◽  
Hongyu Zhang ◽  
Dongxue Zhao ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Carbon Source ◽  
Human Health ◽  
Food Chain ◽  
Metabolic Pathway ◽  
Bacterial Strain ◽  
Sole Carbon Source ◽  
Degradation Pathway ◽  
Aquatic Animal ◽  
Animal Diseases

AbstractSulfamethoxazole (SMX) is the most commonly used antibiotic in worldwide for inhibiting aquatic animal diseases. However, the residues of SMX are difficult to eliminate and may enter the food chain, leading to considerable threats on human health. The bacterial strain Sphingobacterium mizutaii LLE5 was isolated from activated sludge. This strain could utilize SMX as its sole carbon source and degrade it efficiently. Under optimal degradation conditions (30.8 °C, pH 7.2, and inoculum amount of 3.5 × 107 cfu/mL), S. mizutaii LLE5 could degrade 93.87% of 50 mg/L SMX within 7 days. Four intermediate products from the degradation of SMX were identified and a possible degradation pathway based on these findings was proposed. Furthermore, S. mizutaii LLE5 could also degrade other sulfonamides. This study is the first report on (1) degradation of SMX and other sulfonamides by S. mizutaii, (2) optimization of biodegradation conditions via response surface methodology, and (3) identification of sulfanilamide, 4-aminothiophenol, 5-amino-3-methylisoxazole, and aniline as metabolites in the degradation pathway of SMX in a microorganism. This strain might be useful for the bioremediation of SMX-contaminated environment.

scholarly journals Biotransformation Studies on Organochlorine Insecticide, Endosulfan by Indigenous Bacterial Isolate

2017 ◽  
Vol 12 (2) ◽  
pp. 366-376
Author(s):  
M. Supreeth ◽  
N. S. Raju
Keyword(s):  
Bacterial Strain ◽  
Cost Effective ◽  
Organochlorine Insecticide ◽  
Endosulfan Sulfate ◽  
Enrichment Method ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Abiotic Degradation ◽  
Cost Effective Technique ◽  
Microbial Strains

Aerial application of persistent, bioaccumulative organochlorine pesticide endosulfan on cashew plantations to protect it from mosquito bug has led to contamination of soil and water environments in several parts of South Canara region, India. Endosulfan and its toxic residues like endosulfan sulfate are posing several threats to non-target organisms including humans. Biotransformation of toxic compounds using indigenous microbial strains is considered as safe and cost effective technique in bioremediation. In the present work, the bacterial strain designated as ES-1, has been isolated from the soil by enrichment method. The bacterial strain was found to mineralize endosulfan ˃99% of 100 mg/l completely biotically after 14 days of incubation by forming unknown polar metabolites.Whereas, abiotic degradation resulted in formation of a toxic compound, endosulfan sulfate. Based on 16s rDNA sequence analysis, the strain ES-1 showed 99% similarity to Bacillus sp. The results from the work suggest that, this bacterial strain could be employed for remediation of endosulfan contaminated environments.

Production of l-tryptophan by enantioselective hydrolysis of d,l-tryptophanamide using a newly isolated bacterium

2013 ◽  
Vol 67 (10) ◽  
Author(s):  
Jian-Miao Xu ◽  
Ben Chen ◽  
Yuan-Shan Wang ◽  
Yu-Guo Zheng
Keyword(s):  
Enantiomeric Excess ◽  
Fold Increase ◽  
Fermentation Medium ◽  
High Yield ◽  
Enantioselective Hydrolysis ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Enantiomeric Ratio ◽  
Physiological Tests ◽  
Hydrolysis Of

AbstractBacterial strain ZJB-09211 capable of amidase production has recently been isolated from soil samples. The strain is able to asymmetrically hydrolyze l-tryptophanamide from d,l-tryptophanamide to produce l-tryptophan in high yield and with excellent stereoselectivity (enantiomeric excess > 99.9 %, and enantiomeric ratio > 200). Strain ZJB-09211 has been identified as Flavobacterium aquatile based on the cell morphology analysis, physiological tests, and the 16S rDNA sequence analysis. Optimization of the fermentation medium led to an about six-fold increase in the amidase activity of strain ZJB-09211, which reached 501.5 U L−1. Substrate specifity and stereoselectivity investigations revealed that amidase of F. aquatile possessed a broad substrate spectrum and high enantioselectivity.

A Simple Method for Estimation of Lipoxygenase and Cyclo-Oxygenase Pathways in Human Platelets - the Use of Thiobarbituric Acid Reaction

1980 ◽  
Vol 44 (02) ◽  
pp. 111-114 ◽  
Author(s):  
Hiroshi Takayama ◽  
Minoru Okuma ◽  
Haruto Uchino
Keyword(s):  
Time Course ◽  
Normal Values ◽  
Human Platelet ◽  
Thiobarbituric Acid ◽  
Human Platelets ◽  
Optimal Conditions ◽  
Experimental Conditions ◽  
Simple Method ◽  
Acid Reaction ◽  
Optimal Ph

SummaryTo develop a simple method for estimation of platelet lipoxygenase (PLO) and cyclo-oxygenase (PCO) pathways, the arachidonic acid (AA) metabolism of human platelet was investigated under various experimental conditions by the use of the thiobarbituric acid (TBA) reaction and a radioisotope technique. A TBA-reactive substance different from malondialdehyde (MDA) via PCO pathway was detected and shown to be derived from the PLO pathway. Since the optimal pH and time course of its formation were different from those of MDA formation via PCO pathway, PLO and PCO pathways were estimated by quantitating the TBA-reactive substances produced by the incubation of AA either with aspirin-treated platelets or with untreated ones, respectively, each under optimal conditions. Normal values expressed in terms of nmol MDA/108 platelets were 1.17±0.34 (M±SD, n = 31) and 0.79±0.15 (n = 31) for PLO and PCO pathways, respectively.

Enzyme-assisted Extraction for Optimized Recovery of Phenolic Bioactives from Peganum hermala Leaves Using Response Surface Methodology

2018 ◽  
Vol 17 (4) ◽  
pp. 349-354
Author(s):  
Qadir Rahman ◽  
Anwar Farooq ◽  
Amjad Gilani Mazhar ◽  
Nadeem Yaqoob Muhammad ◽  
Ahmad Mukhtar
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Enzyme Concentration ◽  
Coumaric Acid ◽  
Assisted Extraction ◽  
Pre Treatment ◽  
Optimized Conditions ◽  
Enzyme Complexes ◽  
Hydrolysis Of ◽  
Central Composite

This study investigates the effect of enzyme formulations (Zympex-014, Kemzyme dry-plus and Natuzyme) on recovery of phenolics from Peganum hermala (harmal) leaves, under optimized conditions using response surface methodology. As compared to the other enzyme complexes, the yield (34 g/100g) obtained through Zympex-014-assisted extraction was higher under optimized conditions such as time (75 min), temperature (70°C), pH (6.5) and enzyme concentration (5 g/100 g) using central composite design (CCD). Effectiveness of Zympex-014 towards hydrolysis of P. hermala leaves cell wall was examined by analyzing the control and enzyme-treated leave residues using scanning electron microscope (SEM). GC/MS characterization authenticated the presence of quercetin (1.44), gallic acid (0.23), caffeic acid (0.04), cinnamic acid (0.05), m-coumaric acid (0.23) and p-coumaric acid (0.37 μg/g) as the potent phenolics in Zympex-014 based extract. It can be concluded from the findings of the current work that pre-treatment of P. hermala leaves with Zympex-014 significantly enhanced the recovery of phenolics that supports its potential uses in the nutra-pharamaceutical industry.

Papaya shoot tip associated endophytic bacteria isolated from in vitro cultures and host–endophyte interaction in vitro and in vivo

2007 ◽  
Vol 53 (3) ◽  
pp. 380-390 ◽  
Author(s):  
Pious Thomas ◽  
Sima Kumari ◽  
Ganiga K. Swarna ◽  
T.K.S. Gowda
Keyword(s):  
Culture Medium ◽  
Carica Papaya ◽  
In Vitro Cultures ◽  
Dependent Manner ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Single Organism ◽  
Dose Dependent

Fourteen distinct bacterial clones were isolated from surface-sterilized shoot tips (~1 cm) of papaya (Carica papaya L. ‘Surya’) planted on Murashige and Skoog (MS)-based papaya culture medium (23/50 nos.) during the 2–4 week period following in vitro culturing. These isolates were ascribed to six Gram-negative genera, namely Pantoea ( P. ananatis ), Enterobacter ( E. cloacae ), Brevundimonas ( B. aurantiaca ), Sphingomonas , Methylobacterium ( M. rhodesianum ), and Agrobacterium ( A. tumefaciens ) or two Gram-positive genera, Microbacterium ( M. esteraromaticum ) and Bacillus ( B. benzoevorans ) based on 16S rDNA sequence analysis. Pantoea ananatis was the most frequently isolated organism (70% of the cultures) followed by B. benzoevorans (13%), while others were isolated from single stocks. Bacteria-harboring in vitro cultures often showed a single organism. Pantoea, Enterobacter, and Agrobacterium spp. grew actively on MS-based normal papaya medium, while Microbacterium, Brevundimonas, Bacillus, Sphingomonas, and Methylobacterium spp. failed to grow in the absence of host tissue. Supplying MS medium with tissue extract enhanced the growth of all the organisms in a dose-dependent manner, indicating reliance of the endophyte on its host. Inoculation of papaya seeds with the endophytes (20 h at OD550 = 0.5) led to delayed germination or slow seedling growth initially. However, the inhibition was overcome by 3 months and the seedlings inoculated with Pantoea, Microbacterium, or Sphingomonas spp. displayed significantly better root and shoot growths.

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