Biotransformation of 3-cyanopyridine to nicotinic acid using whole-cell nitrilase of Gordonia terrae mutant MN12.

In the present study, the Gordonia terrae was subjected to chemical mutagenesis using ethyl methane sulfonate (EMS) and methyl methane sulfonate (MMS), N-methyl-N-nitro-N-nitrosoguanidine (MNNG), 5-bromouracil (5-BU) and hydroxylamine with the aim of improving the catalytic efficiency of its nitrilase for conversion of 3-cyanopyridine to nicotinic acid. A mutant MN12 generated with MNNG exhibited increase in nitrilase activity from 0.5 U/mg dcw (dry cell weight) (in the wild G. terrae) to 1.33 U/mg dcw. Further optimizations of culture conditions using response surface methodology enhanced the enzyme production to 1.2-fold. Whole-cell catalysis was adopted for bench-scale synthesis of nicotinic acid, and 100% conversion of 100 mM 3-cyanopyridine was achieved in potassium phosphate buffer (0.1 M, pH 8.0) at 40 °C in 15 min. The whole-cell nitrilase of the mutant MN12 exhibited higher rate of product formation and volumetric productivity, i.e., 24.56 g/h/g dcw and 221 g/L as compared to 8.95 g/h/g dcw and 196.8 g/L of the wild G. terrae. The recovered product was confirmed by HPLC, FTIR and NMR analysis with high purity (> 99.9%). These results indicated that the mutant MN12 of G. terrae as whole-cell nitrilase is a very promising biocatalyst for the large-scale synthesis of nicotinic acid.

A Chinese patient with peritoneal dialysis-related peritonitis caused by Gordonia terrae: a case report.

BACKGROUND: Gordonia terrae is a rare cause of clinical infections, with only 23 reported cases. We report the first case of peritoneal dialysis-related peritonitis caused by Gordonia terrae in mainland China. CASE PRESENTATION: A 52-year-old man developed peritoneal dialysis-related peritonitis and received preliminary antibiotic treatment. After claiming that his symptoms had been resolved, the patient insisted on being discharged (despite our recommendations) and did not receive continued treatment after leaving the hospital. A telephone follow-up with the patient's relatives revealed that the patient died 3 months later. Routine testing did not identify the bacterial strain responsible for the infection, although matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identified the strain as Gordonia rubropertincta. However, a 16S rRNA sequence analysis using an isolate from the peritoneal fluid culture revealed that the responsible strain was actually Gordonia terrae. Similar to this case, all previously reported cases have involved a delayed diagnosis and initial treatment failure, and the definitive diagnosis required a 16S rRNA sequence analysis. Changes from an inappropriate antibiotic therapy to an appropriate one have relied on microbiological testing and were performed 7-32 days after the initial treatment. CONCLUSIONS: The findings from our case and the previously reported cases indicate that peritoneal dialysis-related peritonitis caused by Gordonia terrae can be difficult to identify and treat. It may be especially challenging to diagnose these cases in countries with limited diagnostic resources.

Madura foot caused by Gordonia terrae misdiagnosed as Nocardia.

Actinomycetomas are soft tissue bacterial infections that are in the differential for unusual masses of the extremities. Typical infectious agents include Actinomyces and Nocardia and are treated with long-term antibiotics. We report a rare case of Gordonia actinomycetoma that was misdiagnosed as Nocardia and subsequently required surgical excision in addition to antibiotic therapy.

Gordonia terrae kidney graft abscess in a renal transplant patient.

We present the first report, to our knowledge, of a renal abscess cause by an infection from Gordonia terrae in a kidney transplant patient. The patient simultaneously had pulmonary tuberculosis and a perirenal allograft abscess caused by G. terrae. After treatment with imipenem, in addition to anti-tuberculous drugs, the patient was cured.

A Patient of Spontaneous Bacterial Peritonitis in Hepatitis C Cirrhosis Caused by Gordonia terrae: A Case Report.

Background: Gordonia terrae is an opportunistic pathogen that rarely causes clinical infections. Here, we first report a case of spontaneous bacterial peritonitis in patients with hepatitis C cirrhosis caused by Gordonia terrea. Case Presentation: A 71-year-old male patient was diagnosed with spontaneous bacteria peritonitis secondary to hepatitis C cirrhosis. The result of bacterial culture in ascites was positive, and the pathogenic bacteria was preliminarily identified as the Gordonia genus by matrix-assisted laser desorption ionization-time of flight mass spectrometry. After 16S rRNA sequencing analysis, it was determined to be the Gordonia terrea. Symptoms relieved after treatment with ceftazidime. Conclusion: This case indicates that the clinical infections caused by Gordonia terrea should be brought to the forefront. Accurate and rapid bacterial identification results are highly beneficial to the diagnosis and therapeutic regime.

Focusing on Gordonia Infections: Distribution, Antimicrobial Susceptibilities and Phylogeny.

The immunosuppression conditions and the presence of medical devices in patients favor the Gordonia infections. However, the features of this aerobic actinomycete have been little explored. Strains (n = 164) were characterized with 16S rDNA and secA1 genes to define their phylogenetic relationships, and subjected to broth microdilution to profile the antimicrobial susceptibilities of Gordonia species that caused infections in Spain during the 2005-2021 period. Four out of the eleven identified species were responsible for 86.0% of the infections: Gordonia sputi (53.0%), Gordonia bronchialis (18.3%), Gordonia terrae (8.5%) and Gordonia otitidis (6.1%). Respiratory tract infections (61.6%) and bacteremia (21.9%) were the most common infections. The secA1 gene resolved the inconclusive identification, and two major clonal lineages were observed for G. sputi and G. bronchialis. Species showed a wide antimicrobial susceptibility profile. Cefoxitin resistance varies depending on the species, reaching 94.2% for G. sputi and 36.0% for G. terrae. What is noteworthy is the minocycline resistance in G. sputi (11.5%), the clarithromycin resistance in G. bronchialis secA1 lineage II (30.0%) and the amoxicillin-clavulanate and cefepime resistance in G. terrae (21.4% and 42.8%, respectively). G. sputi and G. bronchialis stand out as the prevalent species causing infections in Spain. Resistance against cefoxitin and other antimicrobials should be considered.

An improved process for synthesis of nicotinic acid using hyper induced whole cell nitrilase of Gordonia terrae MTCC8139.

Nitrilase mediated synthesis of nicotinic acid (vitamin B3) from 3-cyanopyridine has emerged as promising viable alternative to its chemical synthesis. In the present investigation, the nitrilase production in Gordonia terrae MTCC8139 has been increased by two fold with inducer feeding approach [i.e. the addition of 0.5% (v/v) isobutyronitrile as inducer at 0, 16 and 24 h of incubation of the culture]. The use of hyper induced whole cell nitrilase of G. terrae as biocatalyst (10 U per ml reaction) to synthesize nicotinic acid from 3-cyanopyridine in a fed batch reaction at one litre scale resulted in accumulation of 1.65 M (202 g) nicotinic acid in 330 min. The catalytic productivity of hyper induced whole cell nitrilase was increased from 8.95 to 15.3 g/h/g dcw and the reaction time was reduced to half. This is the highest productivity of nicotinic acid in a nitrilase mediated process so far reported. The achievements of the present investigation will lead to mitigate the cost of nitrilase vis-a-vis nicotinic acid production at large scale.

Isolation and identification of the alga-symbiotic bacterium Gordonia and characterisation of its exopolysaccharide.

An exopolysaccharide (EPS)-producing bacterium TD18, isolated from the culture broth of green alga Scenedesmus obliquus, was identified as Gordonia terrae based on the 100% identity of 16S rRNA sequences and designated Gordonia terrae TD18. The results of compositional and structural analyses and physiochemical tests show that (1) the exopolysaccharide produced by G. terrae TD18 (TD18-EPS) is an acidic hetero-polysaccharide with a molecular weight of 23 kDa, consisting of glucose, mannose, galactose and glucuronic acid, and (2) TD18-EPS is of high thermal stability with a degradation temperature of 308 °C, the solution of which is non-Newtonian pseudoplastic fluid exhibiting good emulsifying properties over a wide range of temperatures, pH and NaCl concentrations. Hence, Gordonia terrae TD18 is the first alga-symbiotic Gordonia strain identified thus far, while TD18-EPS is unique in terms of composition and structure, different from the known Gordonia EPS, with excellent physiochemical properties and thus has potential applications in industry.

Exploring the fermentation characteristics of a newly isolated marine bacteria strain, Gordonia terrae TWRH01 for carotenoids production.

Carotenoids serve as one of the most important group of naturally-occurring lipid-soluble pigments which exhibit great biological activities such as antioxidant, anti-inflammatory and provitamin A activities. Owing to their advantageous health effects, carotenoids are widely applied in various industries. Microbial carotenoids synthesis therefore has attracted increasing attention in recent years. In the present study, a marine microorganism originally isolated from seawater in northern Taiwan was determined to be a strain of Gordonia terrae based on its 16S rRNA gene sequence. The strain G. terrae TWRH01 has the ability to synthesize and accumulate the intracellular pigments was identified by gas chromatography-mass spectrometry (GC-MS). The biochemical production characteristics of this strain were studied by employing different fermentation strategies. Findings suggested that G. terrae TWRH01 can actively grow and efficiently synthesize carotenoids in medium adjusted to pH 7 containing 16 g L-1 sucrose as the carbon source, 16 g L-1 yeast extract as the nitrogen source, 0.6 M NaCl concentration, and supplemented with 0.45% (v/v) 1 M CaCl2. Results revealed that the optimization of fermentation yielded 15.29 g L-1 dry biomass and 10.58 µmol L-1 relative ß-carotene concentration. According to GC-MS analysis, the orange-red colored pigments produced were identified as carotenoid derivatives, mainly echinenone and adonixanthin 3'-ß-d-glucoside. Therefore, the new bacterial strain showed a highly potential bioresource for the commercial production of natural carotenoids.

Bioremediation of di-(2-ethylhexyl) phthalate contaminated red soil by Gordonia terrae RL-JC02: Characterization, metabolic pathway and kinetics.

Di-(2-ethylhexyl) phthalate (DEHP) is the most widely used plasticizer and a representative endocrine disrupting chemical. The toxicological effects of DEHP on environmental and human health have been widely investigated. In this study, the DEHP-degrading bacterial strain RL-JC02 was isolated from red soil with long-term usage of plastic mulch, and it was identified as Gordonia terrae by 16S rRNA gene analysis coupled with physiological and biochemical characterization. The biodegrading capacity of different phthalic acid esters and related intermediates was investigated as well as the performance of strain RL-JC02 under different environmental conditions, such as temperature, pH, salinity and DEHP concentration. Specifically, strain RL-JC02 showed good tolerance to low pH, with 86.6% of DEHP degraded under the initial pH of 5.0 within 72 h. The metabolic pathway of DEHP was examined by metabolic intermediate identification via a high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) analysis in which DEHP was hydrolyzed into phthalic acid (PA) and 2-ethylhexanol (2-EH) via mono (2-ethylhexyl) phthalate (MEHP). PA and 2-EH were further utilized through the protocatechuic acid metabolic pathway and ß-oxidation via protocatechuic acid and 2-ethylhexanoic acid, respectively. The application potential of strain RL-JC02 was confirmed through the bioremediation of artificial DEHP-contaminated red soil showing 91.8% DEHP degradation by strain RL-JC02 within 30 d. The kinetics analysis of DEHP degradation by strain RL-JC02 in soil demonstrated that the process followed the modified Gompertz model. Meanwhile, the cell concentration monitoring of strain RL-JC02 in soil with absolute quantification polymerase chain reaction (qPCR) suggested that strain RL-JC02 survived well during bioremediation. This study provides sufficient evidence of a robust degrader for the bioremediation of PAE-contaminated red soil.

Substrate specificity of ß-glucosidase from Gordonia terrae for ginsenosides and its application in the production of ginsenosides Rg3, Rg2, and Rh1 from ginseng root extract.

A ß-glucosidase from Gordonia terrae was cloned and expressed in Escherichia coli. The recombinant enzyme with a specific activity of 16.4 U/mg for ginsenoside Rb1 was purified using His-trap chromatography. The purified enzyme specifically hydrolyzed the glucopyranosides at the C-20 position in protopanaxadiol (PPD)-type ginsenosides and hydrolyzed the glucopyranoside at the C-6 or C-20 position in protopanaxatriol (PPT)-type ginsenosides. The reaction conditions for the high-level production of Rg3 from Rb1 by the enzyme were pH 6.5, 30°C, 20 mg/ml enzyme, and 4 mg/ml Rb1. Under these conditions, G. terrae ß-glucosidase completely converted Rb1 and Re to Rg3 and Rg2, respectively, after 2.5 and 8 h, respectively. Moreover, the enzyme converted Rg1 to Rh1 at 1 h with a molar conversion yield of 82%. The enzyme at 10 mg/ml produced 1.16 mg/ml Rg3, 1.47 mg/ml Rg2, and 1.17 mg/ml Rh1 from Rb1, Re, and Rg1, respectively, in 10% (w/v) ginseng root extract at pH 6.5 and 30°C after 33 h with molar conversion yields of 100%, 100%, and 77%, respectively. The combined molar conversion yield of Rg2, Rg3, and Rh1 from total ginsenosides in 10% (w/v) ginseng root extract was 68%. These above results suggest that this enzyme is useful for the production of ginsenosides Rg3, Rg2, and Rh1.