Intracellular degradation of two structurally different polyhydroxyalkanoic acids accumulated in Pseudomonas putida and Pseudomonas citronellolis from mixtures of octanoic acid and 5-phenylvaleric acid

From a set of mixed carbon sources, 5-phenylvaleric acid (PV) and octanoic acid (OA), polyhydroxyalkanoic acid (PHA) was separately accumulated in the two pseudomonads Pseudomonas putida BM01 and Pseudomonas citronellolis (ATCC 13674) to investigate any structural difference between the two PHA accumulated under a similar culture condition using one-step culture technique. The resulting polymers were isolated by chloroform solvent extraction and characterized by fractional precipitation and differential scanning calorimetry. The solvent fractionation analysis showed that the PHA synthesized by P. putida was separated into two fractions, 3-hydroxy-5-phenylvalerate (3HPV))-rich PHA fraction in the precipitate phase and 3-hydroxyoctanoate (3HO)-rich PHA fraction in the solution phase whereas the PHA produced by P. citronellolis exhibited a rather little compositional separation into the two phases. According to the thermal analysis, the P. putida PHA exhibited two glass transitions indicative of the PHA not being homogeneous whereas the P. citronellolis PHA exhibited only one glass transition. It was found that the structural heterogeneity of the P. putida PHA was caused by a significant difference in the assimilation rate between PV and OA. The structural heterogeneity present in the P. putida PHA was also confirmed by a first order degradation kinetics analysis of the PHA in the cells. The two different first-order degradation rate constants (k₁), 0.087 and 0.015/h for 3HO- and 3HPV-unit, respectively, were observed in a polymer system over the first 20 h of degradation. In the later degradation period, the disappearance rate of 3HO-unit was calculated to be 0.020 h. The k₁ value of 0.083/h, almost the same as for the 3HO-unit in the P. putida PHA, was obtained for the P(3HO) accumulated in P. putida BM01 grown on OA as the only carbon source. In addition, the k₁ value of 0.015/h for the 3HPV-unit in the P. putida PHA, was also close to 0.019/h for the P(3HPV) homopolymer accumulated in P. putida BM01 grown on PV plus butyric acid. On the contrary, the k₁ values for the P. citronellolis PHA were determined to be 0.035 and 0.029/h for 3HO- and 3HPV-unit, respectively, thus these two relatively close values implying a random copolymer nature of the P. citronellolis PHA. In addition, the faster degradation of P(3HO) than P(3HPV) by the intracellular P. putida PHA depolymerase indicates that the enzyme is more specific against the aliphatic PHA than the aromatic PHA.     

Biocontrol of <Emphasis Type="Italic">Meloidogyne javanica</Emphasis> by <Emphasis Type="Italic">Rhizobium</Emphasis> and plant growth-promoting rhizobacteria on lentil

Biocontrol of the root-knot nematode Meloidogyne javanica was studied on lentil using plant growth-promoting rhizobacteria (PGPR) namely Pseudomonas putida, P. alcaligenes, Paenibacillus polymyxa and Bacillus pumilus and root nodule bacterium Rhizobium sp. Pseudomonas putida caused greater inhibitory effect on the hatching and penetration of M. javanica followed by P. alcaligenes, P. polymyxa and B. pumilus. Inoculation of any PGPR species alone or together with Rhizobium increased plant growth both in M. javanica-inoculated and -uninoculated plants. Inoculation of Rhizobum caused greater increase in plant growth than caused by any species of plant growth-promoting rhizobacteria in nematode-inoculated plants. Among PGPR, P. putida caused greater increase in plant growth and higher reduction in galling and nematode multiplication followed by P. alcaligenes, P. polymyxa and B. pumilus. Combined use of Rhizobium with any species of PGPR caused higher reduction in galling and nematode multiplication than their individual inoculation. Use of Rhizobium plus P. putida caused maximum reduction in galling and nematode multiplication followed by Rhizobium plus P. alcaligens. Pseudomonas putida caused greater root colonization and siderophore production followed by P. alcaligenes, P. polymyxa and B. pumilus. Analysis of the protein bands of these four species by SDS-PAGE revealed that P. putida had a different protein band profile compared to the protein profiles of P. alcaligenes, P. polymyxa and B. pumilus. However, the protein profiles of P. acaligenes, P. polymyxa and B. pumilus were similar.     

The mechanism of action of hexahydro-1,3,5-triethyl-s-triazine

Summary The mechanism of antimicrobial action of hexahydro-1,3,5-triethyl-s-triazine (HHTT) was studied using the HHTT-resistant isolate,Pseudomonas putida 3-T-15², its HHTT-sensitive, novobiocin-cured derivative,P. putida 3-T-15² 11:21,P. putida ATCC 12633,Pseudomonas aeruginosa PA01 andEscherichia coli J53 (RP4). HHTT was oxidized byP. putida 3-T-15², while respiration ofP. putida 3-T-15² 11:21 was inhibited by HHTT. Chemical assays showed that HHTT released formaldehyde.P. putida 3-T-15² was highly resistant to formaldehyde, whileP. putida 3-T-15² 11:21 was highly sensitive to formaldehyde. Both HHTT and formaldehyde acted similarly to inhibit proline uptake in bacterial cells and to inhibit the synthesis of the inducible enzymes, -galactosidase and glucose-6-phosphate dehydrogenase. HHTT did not have uncoupler-like activity.P. putida 3-T-15² used either HHTT or ethylamine, a component of HHTT, as a nitrogen source for growth, but neither HHTT, ethylamine or formaldehyde served as a carbon and energy source for growth. We concluded that a major mechanism of antimicrobial action of HHTT was through its degradation product, formaldehyde.     

Enhancement ofcis,cis-muconate productivity by overexpression of catechol 1,2-dioxygenase inPseudomonas putida BCM114

For enhancement ofcis,cis-muconate productivity from benzoate, catechol 1,2-dioxygenase (C12O) which catalyzes the rate-limiting step (catechol conversion tocis,cis-muconate) was cloned and expressed in recombinantPseudomonas putida BCM114. At higher benzoate concentrations (more than 15 mM),cis,cis-muconate productivity gradually decreased and unconverted catechol was accumulated up to 10 mM in the case of wildtypeP. putida BM014, whereascis,cis-muconate productivity continuously increased and catechol was completely transformed tocis,cis-muconate forP. putida BCM114. Specific C12O activity ofP. putida BCM114 was about three times higher than that ofP. putida BM014, and productivity was enhanced more than two times.     

Nucleotide sequence analysis and comparison of the lexA genes from Salmonella typhimurium, Erwinia carotovora, Pseudomonas aeruginosa and Pseudomonas putida.

Summary The complete nucleotide sequences of the lexA genes from Salmonella typhimurium, Erwinia carotovora, Pseudomonas aeruginosa and Pseudomonas putida were determined; the DNA sequences of the lexA genes from these bacteria were 86%, 76%, 61% and 59% similar, respectively, to the Escherichia coli K12 gene. The predicted amino acid sequences of the S. typhimurium, E. carotovora and P. putida LexA proteins are 202 residues long whereas that of P. aeruginosa is 204. Two putative LexA repressor binding sites were localized upstream of each of the heterologous genes, the distance between them being 5 by in S. typhimurium and E. carotovora, as in the lexA gene of E. coli, and 3 by in P. putida and P. aeruginosa. The first lexA site present in the lexA operator of all five bacteria is very well conserved. However, the second lexA box is considerably more variable. The Ala-84 — Gly-85 bond, at which the LexA repressor of E. coli is cleaved during the induction of the SOS response, is also found in the LexA proteins of S. typhimurium and E. carotovora. Likewise, the amino acids Ser-119 and Lys-156 are present in all of these three LexA repressors. These residues also exist in the LexA proteins of P. putida and P. aeruginosa, but they are displaced by 4 and 6 residues, respectively. Furthermore, the structure and sequence of the DNA-binding domain of the LexA repressor of E. coli are highly conserved in the S. typhimurium, E. carotovora, P. aeruginosa and P. putida LexA proteins.     

Characteristics of a newly created bioluminescent Pseudomonas putida harboring TOL plasmid for use in analysis of a bioaugmentation system

Insertion of a bacterial lux operon into the chromosome of Pseudomonas putida mt-2 holding TOL plasmid, yielded a new bioluminescent strain of P. putida BLU. Both in the cultures containing toluene and m-toluic acid as the sole carbon sources, P. putida BLU showed the same specific growth rate and cell yield as those of the wild strain. The bioluminescence output in the cell growth phases correlated with the cell concentration, indicating that the bioluminescent P. putida BLU can be monitored and quantified in a mixed culture in real time by the luminescence detection.     

Comparative effectiveness of <Emphasis Type="Italic">Pseudomonas</Emphasis> and <Emphasis Type="Italic">Serratia</Emphasis> sp. containing ACC-deaminase for improving growth and yield of wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) under salt-stressed conditions

Ethylene synthesis is accelerated in response to various environmental stresses like salinity. Ten rhizobacterial strains isolated from wheat rhizosphere taken from different salt affected areas were screened for growth promotion of wheat under axenic conditions at 1, 5, 10 and 15 dS m⁻¹. Three strains, i.e., Pseudomonas putida (N21), Pseudomonas aeruginosa (N39) and Serratia proteamaculans (M35) showing promising performance under axenic conditions were selected for a pot trial at 1.63 (original), 5, 10 and 15 dS m⁻¹. Results showed that inoculation was effective even in the presence of higher salinity levels. P. putida was the most efficient strain compared to the other strains and significantly increased the plant height, root length, grain yield, 100-grain weight and straw yield up to 52, 60, 76, 19 and 67%, respectively, over uninoculated control at 15 dS m⁻¹. Similarly, chlorophyll content and K⁺/Na⁺ of leaves also increased by P. putida over control. It is highly likely that under salinity stress, 1-aminocyclopropane-1-carboxylic acid-deaminase activity of these microbial strains might have caused reduction in the synthesis of stress (salt)-induced inhibitory levels of ethylene. The results suggested that these strains could be employed for salinity tolerance in wheat; however, P. putida may have better prospects in stress alleviation/reduction.     

Characterization of type II protein secretion (xcp) genes in the plant growth-stimulatingPseudomonas putida, strain WCS358

InPseudomonas aeruginosa, the products of thexcp genes are required for the secretion of exoproteins across the outer membrane. Despite structural conservation of the Xcp components, secretion of exoproteins via the Xcp pathway is generally not found in heterologous organisms. To study the specificity of this protein secretion pathway, thexcp genes of another fluorescent pseudomonad, the plant growth-promotingPseudomonas putida strain WCS358, were cloned and characterized. Nucleotide sequence analysis revealed the presence of at least five genes, i.e.,xcpP, Q, R, S, andT, with homology toxcp genes ofP. aeruginosa. Unlike the genetic organization inP. aeruginosa, where thexcp cluster consists of two divergently transcribed operons, thexcp genes inP. putida are all oriented in the same direction, and probably comprise a single operon. Upstream ofxcpP inP. putida, an additional open reading frame, with no homolog inP. aeruginosa, was identified, which possibly encodes a lipoprotein. Mutational inactivation ofxcp genes inP. putida did not affect secretion, indicating that no proteins are secreted via the Xcp system under the growth conditions tested, and that an alternative secretion system is operative. To obtain some insight into the secretory pathway involved, the amino acid sequence of the N-terminus of the major extracellular protein was determined. The protein could be identified as flagellin. Mutations in thexcpQ andR genes ofP. aeruginosa could not be complemented by introduction of the correspondingxcp genes ofP. putida. However, expression of a hybrid XcpR protein, composed of the N-terminal one-third ofP. aeruginosa XcpR and the C-terminal two-thirds ofP. putida XcpR, did restore protein secretion in aP. aeruginosa xcpR mutant.     

Performance evaluation of potent phosphate solubilizing bacteria in potato rhizosphere

Three phosphate solubilizing bacterial isolates identified as Pantoea agglomerans strain P5, Microbacterium laevaniformans strain P7 and Pseudomonas putida strain P13 were assessed for mutual relationships among them, competitiveness with soil microorganisms and associations with plant root using luxAB reporter genes for follow-up studies. Synergism between either P. agglomerans or M. laevaniformans, as acid-producing bacteria, and P. putida, as a strong phosphatase producer, was consistently observed both in liquid culture medium and in root rhizosphere. All laboratory, greenhouse and field experiments proved that these three isolates compete well with naturally occurring soil microorganisms. Consistently, the combinations of either P. agglomerans or M. laevaniformans strains with Pseudomonas putida led to higher biomass and potato tuber in greenhouse and in field trials. It is conceivable that combinations of an acid- and a phosphatase-producing bacterium would allow simultaneous utilization of both inorganic and organic phosphorus compounds preserving the soil structure.     

Induction of ortho- and meta-cleavage pathways in Pseudomonas in biodegradation of high benzoate concentration: MS identification of catabolic enzymes

The degradation pathways of benzoate at high concentration in Pseudomonas putida P8 were directly elucidated through mass spectrometric identification of some key catabolic enzymes. Proteins from P. putida P8 grown on benzoate or succinate were separated using two-dimensional gel electrophoresis. For cells grown on benzoate, eight distinct proteins, which were absent in the reference gel patterns from succinate-grown cells, were found. All the eight proteins were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as catabolic enzymes involved in benzoate degradation. Among them, CatB (EC5.5.1.1), PcaI (EC2.8.3.6), and PcaF (EC2.3.1.174) were the enzymes involved in the ortho-cleavage pathway; DmpC (EC1.2.1.32), DmpD (EC3.1.1.-), DmpE (EC4.2.1.80), DmpF (EC1.2.1.10), and DmpG (EC4.1.3.-) were the meta-cleavage pathway enzymes. In addition, enzyme activity assays showed that the activities of both catechol 1,2-dioxygenase (C12D; EC1.13.11.1) and catechol 2,3-dioxygenase (C23D; EC1.13.11.2) were detected in benzoate-grown P. putida cells, undoubtedly suggesting the simultaneous expression of both the ortho- and the meta-cleavage pathways in P. putida P8 during the biodegradation of benzoate at high concentration.     

Production of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from Gluconate and Glucose by Recombinant Aeromonas hydrophila and Pseudomonas putida

Aeromonas hydrophila 4AK4 and Pseudomonas putida GPp104 were genetically engineered to synthesize poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) using gluconate and glucose rather than fatty acids. A truncated tesA gene, encoding cytosolic thioesterase I of Escherichia coli which catalyzes the conversion of acyl-ACP into free fatty acids, was introduced into A. hydrophila 4AK4. When grown in gluconate, the recombinant A. hydrophila 4AK4 synthesized 10% (w/w) PHBHHx containing 14% (mol/mol) 3-hydroxyhexanoate. If additional PHBHHx synthesis genes, phaPCJ, were over-expressed with the truncated tesA in A. hydrophila 4AK4, the PHBHHx content increased to 15% (w/w) and contained 19% (mol/mol) 3-hydroxyhexanoate. Recombinant P. putida GPp104 harboring phaC encoding PHBHHx synthase of A. hydrophila, phaB encoding acetoacetyl-CoA reductase of Wautersia eutropha and phaG encoding 3-hydroxyacyl-ACP-CoA transferase of P. putida, synthesized 19% (w/w) PHBHHx containing 5% (mol/mol) 3-hydroxyhexanoate from glucose. The results suggest that the engineered pathways were applicable to synthesize PHBHHx from unrelated carbon sources such as gluconate and glucose.     

Microbial transformation of benzene to <Emphasis Type="Italic">cis</Emphasis>-3,5-cyclohexadien-1,2-diols by recombinant bacteria harboring toluene dioxygenase gene <Emphasis Type="Italic">tod</Emphasis>

Toluene dioxygenase (TDO) catalyzes asymmetric cis-dihydroxylation of aromatic compounds. To achieve high efficient biotransformation of benzene to benzene cis-diols, Pseudomonas putida KT2442, Pseudomonas stutzeri 1317, and Aeromonas hydrophila 4AK4 were used as hosts to express TDO gene tod. Plasmid pSPM01, a derivative of broad-host plasmid pBBR1MCS-2 harboring tod from plasmid pKST11, was constructed and introduced into the above three strains. Their abilities to catalyze the biotransformation of benzene to benzene cis-diols, namely, cis-3,5-cyclohexadien-1,2-diols abbreviated as DHCD, were examined. In shake-flask cultivation under optimized culture media and growth condition, benzene cis-diols production by recombinant P. putida KT2442 (pSPM01), P. stutzeri 1317 (pSPM01), and A. hydrophila 4AK4 (pSPM01) were 2.68, 2.13, and 1.17 g/l, respectively. In comparison, Escherichia coli JM109 (pSPM01) and E. coli JM109 (pKST11) produced 0.45 and 0.53 g/l of DHCD, respectively. When biotransformation was run in a 6-l fermenter, DHCD production in P. putida KT2442 (pSPM01) was approximately 60 g/l; this is the highest DHCD production yield reported so far.     

Maintenance and killing efficiency of conditional lethal constructs inPseudomonas putida

Summary Conditional lethal (suicidal) genetic constructs were designed and employed in strains of Pseudomonads as models for containment of geneticallyengineerd microbes that may be deliberately released into the environment. A strain ofPseudomonas putida was formed with a suicide vector designated pBAP24h that was constructed by cloning the host killing gene (hok) into the RSF1010 plasmid pVDtac24 and placing it under the control of thetac promoter. Afterhok induction inP. putida only 40% of surviving cells continued to bear thehok sequences within 4 h of induction; in contrast, 100% of the cells in uninduced controls borehok. A few survivors that demonstrated resistance tohok-induced killing developed inP. putida, which may have been due to a mutation or physiological adaptation that rendered the membrane resistant tohok. Conditional lethal strains ofP. putida also were formed by insertinggef (a chromosomal homolog ofhok) under the control of thetac promoter into the chromosome using a transposon. Constructs with chromosomalgef, as well as an RK2-derived plasmid construct containinggef, were only marginally more stable than thehok constructs; they were effective in killingP. putida when induced and within 2 h post-induction killing from eithergef construct resulted in a 10³–10⁵-fold reduction in viable cell count compared to uninduced controls.     

Engineering alternative butanol production platforms in heterologous bacteria

Alternative microbial hosts have been engineered as biocatalysts for butanol biosynthesis. The butanol synthetic pathway of Clostridium acetobutylicum was first re-constructed in Escherichia coli to establish a baseline for comparison to other hosts. Whereas polycistronic expression of the pathway genes resulted in the production of 34 mg/L butanol, individual expression of pathway genes elevated titers to 200 mg/L. Improved titers were achieved by co-expression of Saccharomyces cerevisiae formate dehydrogenase while overexpression of E. coli glyceraldehyde 3-phosphate dehydrogenase to elevate glycolytic flux improved titers to 580 mg/L. Pseudomonas putida and Bacillus subtilis were also explored as alternative production hosts. Polycistronic expression of butanol biosynthetic genes yielded butanol titers of 120 and 24 mg/L from P. putida and B. subtilis, respectively. Production in the obligate aerobe P. putida was dependent upon expression of bcd-etfAB. These results demonstrate the potential of engineering butanol biosynthesis in a variety of heterologous microorganisms, including those cultivated aerobically.     

Microbial production of <Emphasis Type="Italic">cis</Emphasis>-1,2-dihydroxy-cyclohexa-3,5-diene-1-carboxylate by genetically modified <Emphasis Type="Italic">Pseudomonas putida</Emphasis>

Arene cis-diols are interesting chemicals because of their chiral structures and great potentials in industrial synthesis of useful chiral chemical products. Pseudomonas putida KT2442 was genetically modified to transform benzoic acid (benzoate) to 1,2-dihydroxy-cyclohexa-3,5-diene-1-carboxylic acid (DHCDC) or named benzoate cis-diol. BenD gene encoding cis-diol dehydrogenase was deleted to generate a mutant named P. putida KTSY01. Genes benABC encoding benzoate dioxygenase were cloned into plasmid pSYM01 and overexpressed in P. putida KTSY01. The recombinant bacteria P. putida KTSY01 (pSYM01) showed strong ability to transform benzoate to DHCDC. DHCDC of 2.3 g/L was obtained with a yield of 73% after 24 h of cultivation in shake flasks incubated under optimized growth conditions. Transformation of benzoate carried out in a 6-L fermentor using a benzoate fed-batch process produced over 17 g/L DHCDC after 48 h of fermentation. The average DHCDC production rate was 0.356 g L⁻¹ h⁻¹. DHCDC purified from the fermentation broth showed a purity of more than 95%, and its chemical structure was confirmed by nuclear magnetic resonance.     

Regulation of amino acid and glucose dissimilation in so-called ammonifiers and in other soil microorganisms

Pseudomonas acidovorans and P. putida, isolated from an enrichment culture with casein hydrolysate, and Agrobacterium radiobacter and Torulopsis sp., isolated from a glucose enrichment, were compared with respect to the physiology of ammonification. Decreasing ammonifying ability as well as increasing repression of the synthesis of amino acid degrading enzymes by glucose were found in the above order of organisms. In degradation sequences, observed with P. putida and A. radiobacter as test organisms, substances dissimilated prior to others had both, enhancing and repressing effects on the oxidation of the other compounds. This fact was parallelled by the observation, that in these two bacteria, glucose and single amino acids, when added to the same medium, exerted mutual repression of the synthesis of catabolic enzymes of their partners. The ecological significance of this type of regulation has been discussed.     

Inactivation of type I polyhydroxyalkanoate synthase in <Emphasis Type="Italic">Aeromonas hydrophila</Emphasis> resulted in discovery of another potential PHA synthase

Aeromonas hydrophila CGMCC 0911 possessing type I polyhydroxyalkanoate (PHA) synthase (PhaC) produced only PHBHHx from lauric acid but not from glucose. Medium-chain-length (mcl) PHA was produced from lauric acid or glucose only when PhaC of A. hydrophila was inactivated, indicating the existence of another PHA synthase in the wild type. Using PCR cloning strategy, the potential PHA synthase gene (phaC _mcl) was obtained from genomic DNA of the wild type and exhibited strong homology to type II PHA synthase genes of Pseudomonas strains. The phaC _mcl gene was PCR subcloned into plasmid pBBR1MCS2 and expressed in a PHA-negative mutant of Pseudomonas putida. Recombinant P. putida synthesized mcl PHA from gluconate or octanoate. This result proved that wild type A. hydrophila possessed another type II PHA synthase, which was responsible for the synthesis of mcl PHA, besides type I PHA synthase.     

Bacterial Endosymbionts of Pyrodinium bahamense var. compressum

The study presents evidence in support of the bacterial theory associated with the toxicity of Pyrodinium bahamense var. compressum. Bacterial endosymbionts from Philippine P. bahamense var. compressum strain Pbc MZRVA 042595 were isolated and identified via 16S rDNA sequence analysis. Taxonomic diversity of the identified culturable intracellular microbiota associated with Philippine P. bahamense var. compressum was established to be limited to the Phyla Proteobacteria, Actinobacteria, and Firmicutes. Major endosymbionts identified included Moraxella spp., Erythrobacter spp., and Bacillus spp., whereas Pseudomonas putida, Micrococcus spp., and Dietzia maris were identified as minor isolates. All identified strains except D. maris, P. putida, and Micrococcus spp. were shown to contain either saxitoxin or neo saxitoxin or both at levels ≤73 ng/10⁷ bacterial cells based on high-performance liquid chromatography analysis. Paralytic shellfish poisoning-like physiologic reactions in test animals used in the mouse assay were recorded for the endosymbionts except for P. putida. The study is the first to elucidate the possible contribution of bacterial endosymbionts in the toxicity of P. bahamense var. compressum isolated in the Philippines.     

Cosubstrate effects in reductive dehalogenation byPseudomonas putida G786 expressing cytochrome P-450CAM

Cytochrome P-450_CAM was shown to be the primary catalyst mediating reductive dehalogenation of polychlorinated ethanes byPseudomonas putida G786. Under anaerobic conditions, the enzyme catalyzed reductive elimination reactionsin vivo with the substrates hexachloroethane, pentachloroethane, and 1,1,1,2-tetrachloroethane; the products were tetrachloroethylene, trichloroethylene, and 1,1-dichloroethylene, respectively.In vivo reaction rates were determined. No reaction was observed with 1,1,2,2-tetrachloroethane or 1,1,1-trichloroethane. Purified cytochrome P-450_CAM was used to measure dissociation constants of polychlorinated ethanes for the enzyme active site. Observed rates and dissociation constants were used to predict the course of a reaction with the three substrates simultaneously. Data obtained from experiments withP. putida G786 generally followed the simulated reaction curves. Oxygen suppressed the reductive dechlorination reactions and, in the case of 1,1,1,2-tetrachloroethane, 2,2,2-trichloroacetaldehyde was formed. Significant rates of reductive dechlorination were observed at 5% oxygen suggesting that these reactions could occur under partially aerobic conditions. These studies highlight the potential to use an aerobic bacterium,P. putida G786, under a range of oxygen tensions to reductively dehalogenate mixed wastes which are only degraded at very low rates by obligately anaerobic bacteria.Abbreviations GC/MS Gas chromatography/mass spectrometry - P-450_CAM Cytochrome m of the camphor oxidizing system ofP. putida - pca Polychlorinated ethane     

l-Lysine-2-monooxygenase production by strains of Pseudomonas fluorescens and P. putida

Twelve strains of Pseudomonas fluorescens and P. putida were grown in a synthetic medium that contained l-lysine as the only source of carbon and nitrogen, and screened for l-lysine-2-monooxygenase production. Best production was by P. putida BKM B-1458 at 30 IU/g wet wt biomass when grown in a shake-flask but 25 IU/g in a 250-l fermenter.