Diverse bacteria isolated from microtherm oil-production water

In total, 435 pure bacterial strains were isolated from microtherm oil-production water from the Karamay Oilfield, Xinjiang, China, by using four media: oil-production water medium (Cai medium), oil-production water supplemented with mineral salt medium (CW medium), oil-production water supplemented with yeast extract medium (CY medium), and blood agar medium (X medium). The bacterial isolates were affiliated with 61 phylogenetic groups that belong to 32 genera in the phyla Actinobacteria, Firmicutes, and Proteobacteria. Except for the Rhizobium, Dietzia, and Pseudomonas strains that were isolated using all the four media, using different media led to the isolation of bacteria with different functions. Similarly, nonheme diiron alkane monooxygenase genes (alkB/alkM) also clustered according to the isolation medium. Among the bacterial strains, more than 24 % of the isolates could use n-hexadecane as the sole carbon source for growth. For the first time, the alkane-degrading ability and alkB/alkM were detected in Rhizobium, Rhodobacter, Trichococcus, Micrococcus, Enterococcus, and Bavariicoccus strains, and the alkM gene was detected in Firmicutes strains.     

A new cost-effective, selective and differential medium for the isolation of Cronobacter spp

The objective of the present study was to develop a new selective, differential and cost-effective medium (Kim and Rhee — KR-medium) for the isolation of Cronobacter spp. In this new medium, which contained salicin as a differential agent, Cronobacter spp. generated typical colonies with characteristic violet-colored centers surrounded by a transparent to opalescent border, and the growth of other microorganisms (40 strains) was inhibited or produced visually distinguishable colonies. Using healthy and heat- and desiccation-injured cells, the quantity of nutrients was adjusted to determine the optimal recovery rate, selectivity, differentiation and cost-effectiveness. Peptone and salicin concentrations were established as 10 and 8 g/L, respectively. The KR medium was then validated using salicin fermenting organisms, including Cronobacter spp. (52 strains), Enterobacter cloacae (50 strains) and Klebsiella pneumonia (10 strains) isolated from clinical and food specimens. All strains of Cronobacter spp. produced typical colonies and other salicin fermenting organisms were easily distinguishable from Cronobacter spp. with the exception of 2 E. cloacae strains. The verification of KR medium was carried out in powdered infant formula artificially inoculated with healthy, heat-injured, and desiccation-injured Cronobacter spp. and the expected typical colonies were appeared. The KR medium had a high specificity (98%) and sensitivity (100%), with no false-negative results. Moreover, we show that the cost of the KR medium is much lower than that of other selective and differential media. The use of the KR medium for the selective isolation of Cronobacter spp. in laboratories and food industry settings may therefore lessen the financial burden of Cronobacter spp. detection.     

Minimal Growth Temperature, Sodium Chloride Tolerance, pH Sensitivity, and Toxin Production of Marine and Terrestrial Strains of Clostridium botulinum Type C

Minimal growth temperatures of four marine and two terrestrial strains of Clostridium botulinum type C were determined in a laboratory culture medium, fortified egg meat medium (FEM), and in ground haddock. The inoculum equaled 2 × 10⁶ viable spores per tube with five-tube replicate sets. The spores were preheated in aqueous suspension at 71 C for 15 min prior to inoculation to reduce toxin carry-over. Similar results were obtained in both substrates. Both the marine and the terrestrial strains grew at 15.6 C, but only the terrestrial strains grew at 12.8 C. None of the strains grew at 10 C during prolonged incubation. The sodium chloride tolerance and the pH sensitivity of the marine and the terrestrial strains were determined at 30 C. The basal medium consisted of beef infusion broth. The inoculum level equaled 2 × 10⁶ unheated spores per replicate. Growth was inhibited at salt concentrations from 2.5 to 3.0%. The terrestrial strains were more pH-sensitive than the marine strains. Whereas the terrestrial strains failed to grow below pH 5.62, three of the marine strains grew at pH 5.10, but not at pH 4.96, during extended incubation. One marine strain grew at pH 5.25, but not below. FEM and proteose peptone-Trypticase-yeast extract-glucose medium permitted the production of high levels of botulinum toxin among four media tested. Toxin produced by the marine and terrestrial strains showed no increase in toxicity after incubation with trypsin.     

A simple strategy for investigating the diversity and hydrocarbon degradation abilities of cultivable bacteria from contaminated soil

The use of indigenous bacterial strains is a valuable bioremediation strategy for cleaning the environment from hydrocarbon pollutants. The isolation and selection of hydrocarbon-degrading bacteria is therefore crucial for obtaining the most promising strains for site decontamination. Two different media, a minimal medium supplemented with a mixture of polycyclic aromatic hydrocarbons and a MS medium supplemented with triphenyltetrazolium chloride, were used for the isolation of bacterial strains from two hydrocarbon contaminated soils and from their enrichment phases. The hydrocarbon degradation abilities of these bacterial isolates were easily and rapidly assessed using the 2,6-dichlorophenol indophenol assay. The diversity of the bacterial communities isolated from these two soil samples and from their enrichment phases was evaluated by the combination of a bacterial clustering method, fluorescence ITS-PCR, and bacterial identification by 16S rRNA sequencing. Different PCR-based assays were performed in order to detect the genes responsible for hydrocarbon degradation. The best hydrocarbon-degrading bacteria, including Arthrobacter sp., Enterobacter sp., Sphingomonas sp., Pseudomonas koreensis, Pseudomonas putida and Pseudomonas plecoglossicida, were isolated directly from the soil samples on minimal medium. The nahAc gene was detected only in 13 Gram-negative isolates and the sequences of nahAc-like genes were obtained from Enterobacter, Stenotrophomonas, Pseudomonas brenneri, Pseudomonas entomophila and P. koreensis strains. The combination of isolation on minimal medium with the 2,6-dichlorophenol indophenol assay was effective in selecting different hydrocarbon-degrading strains from 353 isolates.     

An in vitro study of Lactobacillus plantarum strains for the presence of plantaricin genes and their potential control of the table olive microbiota

Sixteen Lactobacillus plantarum strains, isolated from fermented table olives, were studied for the presence and expression of genes involved in the production of bacteriocins, pheromones and other peptides. The presence of 13 genes that belong to pln locus was monitored, while for the study of gene expression, producer strains were cultured in growth medium with variant salinity (0, 4, 6, and 8 % NaCl) and pH (3.5, 4.0, 4.5, and 6.4). The effect of producer strain on the growth of indicator microorganisms was evaluated using a well diffusion assay. In parallel, Real-Time PCR was employed to monitor the genetic expression of plnE/F and plnJ/K genes for strains that revealed the highest antimicrobial activity. The well diffusion assay showed that the growth of Lactobacillus pentosus was inhibited by six L. plantarum strains when cultured on control medium (0 % NaCl, pH 6.4). Moreover, when the same growth medium was supplemented with 4 and 6 % NaCl, the growth of L. pentosus was inhibited by three and two L. plantarum strains, respectively. Growth of L. pentosus was favoured when L. plantarum strains were cultured on a growth medium with lowered pH (3.5, 4.0, and 4.5). No inhibition of pathogens was observed, but in a few cases, inhibition of Aureobasidium pullulans was detected. The Real-Time PCR assay revealed that the expression of genes was dependent on producer strains and growth phase, whereas inhibition of indicator strains was enhanced in earlier stages of the growth curve in the presence of NaCl, although similar counts were obtained.     

Distribution of Genes for Synthesis of Trehalose and Mannosylglycerate in Thermus spp. and Direct Correlation of These Genes with Halotolerance

In this study we correlate the presence of genes leading to the synthesis of trehalose and mannosylglycerate (MG) in 17 strains of the genus Thermus with the ability of the strains to grow and accumulate these compatible solutes in a defined medium containing NaCl. The two sets of genes, namely, otsA/otsB for the synthesis of trehalose and mpgS/mpgP for the synthesis of MG, were necessary for the growth of Thermus thermophilus in a defined medium containing up to 6% NaCl. Strains lacking a complete otsA gene did not grow in defined medium containing >2% NaCl. One strain of T. thermophilus lacking the genes for the synthesis of MG did not grow in a medium with >1% NaCl. We did not identify any of these genes in the type strains of the other seven species of Thermus, and none of those strains grew in defined medium with 1% NaCl. The results strongly indicate that the combined accumulation of trehalose and MG is required for optimal osmotic adjustment.     

Comparison of Media for the Isolation of Cryptococcus neoformans

Four media, Staib's Guizotia abyssinica, trypan blue, and Staib's with 2 and 10 mg of methyl violet per liter, were compared for the selective and differential isolation of Cryptococcus neoformans from environmental samples. Trypan blue medium allowed for the differentiation of C. neoformans colonies from Candida albicans colonies several days earlier than did Staib's medium. The addition of methyl violet to Staib's medium was found to be inhibitory to some strains of all species tested. Diphenyl in Staib's medium inhibited the growth of 30 strains of C. neoformans and C. albicans.     

Biofilm Formation by and Antifungal Susceptibility of Candida Isolates from Urine

Biofilm formation (BF) in the setting of candiduria has not been well studied. We determined BF and MIC to antifungals in Candida spp. isolates grown from urine samples of patients and performed a retrospective chart review to examine the correlation with risk factors. A total of 67 Candida spp. isolates were grown from urine samples from 55 patients. The species distribution was C. albicans (54%), C. glabrata (36%), and C. tropicalis (10%). BF varied greatly among individual Candida isolates but was stable in sequential isolates during chronic infection. BF also depended on the growth medium and especially in C. albicans was significantly enhanced in artificial urine (AU) compared to RPMI medium. In nine of the C. albicans strains BF was 4- to 10-fold higher in AU, whereas in three of the C. albicans strains and two of the C. glabrata strains higher BF was measured in RPMI medium than in AU. Determination of the MICs showed that planktonic cells of all strains were susceptible to amphotericin B (AMB) and caspofungin (CASPO) and that three of the C. glabrata strains and two of the C. albicans strains were resistant to fluconazole (FLU). In contrast, all biofilm-associated adherent cells were resistant to CASPO and FLU. The biofilms of 14 strains (28%) were sensitive to AMB (MIC₅₀ of <1 μg/ml). Correlation between degree of BF and MIC of AMB was not seen in RPMI grown biofilms but was present when grown in AU. A retrospective chart review demonstrated no correlation of known risk factors of candiduria with BF in AU or RPMI. We conclude that BF is a stable characteristic of Candida strains that varies greatly among clinical strains and is dependent on the growth medium. Resistance to AMB is associated with higher BF in AU, which may represent the more physiologic medium to test BF. Future studies should address whether in vitro BF can predict treatment failure in vivo.     

Inhibition of Clostridium botulinum by Strains of Clostridium perfringens Isolated from Soil

Thirty-one soil samples were examined for the presence of organisms capable of inhibiting growth and toxin production of strains of Clostridium botulinum type A. Such organisms were found in eight samples of soil. Inhibiting strains of C. perfringens were found in five samples, of C. sporogenes in three and of Bacillus cereus in three. Three of the C. perfringens strains produced an inhibitor effective on all 11 strains of C. botulinum type A against which they were tested, seven of eight proteolytic type B strains, one nonproteolytic type B strain, five of nine type E strains and all seven type F strains, whether proteolytic or nonproteolytic. They did not inhibit any of 26 type C strains, 6 type D strains, 4 type E strains, or 24 C. sporogenes strains. In mixed culture, an inhibitor strain of C. perfringens repressed growth and toxin production by a C. botulinum type A strain even though it was outnumbered by the latter about 40 times. It also repressed growth and toxin production of C. botulinum in mixed culture of soils in which this latter organism naturally occurred when cooked meat medium but not when trypticase medium was used.     

Effect of sodium chloride on growth of heterotrophic marine bacteria

The effect of NaCl on the growth rates and yields of 31 gram-negative, heterotrophic, marine bacteria was determined. The strains used were representative of aerobic genera (Alteromonas, Pseudomonas, Alcaligenes, Bdellovibrio) as well as genera comprised of facultative anaerobes (Beneckea, Photobacterium). Two media were used-the first, a medium designed for the cultivation of marine bacteria and, the second, a medium used for the cultivation of terrestrial strains. These two media differed in the concentrations of divalent cations; the terrestrial medium (TM) contained 2 mM Mg⁺⁺ and 0.55 mM Ca⁺⁺ while the marine medium (MM) contained 50 mM Mg⁺⁺ and 10 mM Ca⁺⁺. The amount of NaCl necessary for optimal growth varied in different strains and was usually considerably higher in TM (100 to 460 mM) than in MM (70 to 300 mM). Many strains which grew in MM and TM had a shorter generation time in the former than in the latter medium. In addition, four strains which grew well in MM usually failed to grow in TM. These results show that higher levels of divalent cations are either essential for growth or stimulate growth rate, indicating that for many marine strains a terrestrial medium modified by the addition of NaCl cannot support optimal growth. Fourteen terrestrial strains of the genera Pseudomonas, Alcaligenes, Acinetobacter, Salmonella, Aeromonas, and Vibrio did not have ionic requirements comparable to those of the marine strains. All of the terrestrial organisms grew in TM without added NaCl (0.068 mM Na⁺ was present as a contaminant). In some terrestrial organisms, growth was stimulated by the addition of NaCl, the highest stimulation being found in Vibrio cholerae. The optimal growth rates and yields for four strains of this species were observed at 2.5 to 5.0 mM NaCl while the growth rates and yields in TM with no added NaCl were 40 to 50% of the optimum.     

Sporulation, Heat Resistance, and Biological Properties of Clostridium perfringens

A sporulation medium for 134 Clostridium perfringens strains, including types A, B, C, D, E, and F, was devised according to Grelet's observation that sporulation occurred when cultural environment became limited in any nutritional requirement indispensable for the growth of the organism. Sporulation took place most prominently when 10% cooked-meat broth (pH 7.2) containing 3% Proteose Peptone and 1% glucose was used for the preculture and 2% Poli Peptone medium (pH 7.8) was used for the subculture medium. Sometimes, terminal spores could be observed. A correlation between sporulation and heat resistance was examined by use of C. perfringens strains isolated from samples heated at different temperatures. Almost all strains isolated from unheated samples and from those heated at lower temperatures gave rise to spores in our sporulation medium, but the spores were weakly heat-resistant, whereas strains isolated from samples heated at 100 C for 60 min were highly heat-resistant but sporulated poorly. A majority of these heat-resistant strains were non-gelatinolytic and definitely salicin-fermenting.     

Chemically Defined Medium for Cultivation of Several Epiphytic and Phytopathogenic Spiroplasmas

A chemically defined medium, LD82, was formulated for in vitro cultivation of spiroplasmas. Medium LD82 supported good growth for four epiphytic and insect-pathogenic spiroplasmas, Spiroplasma floricola 23-6^T, Spiroplasma sp. strain SR3, Spiroplasma sp. strain brevi, and Spiroplasma sp. strain AS576, and of the phytopathogenic spiroplasmas Spiroplasma citri Maroc R8A2^T and PC1. Titers of all six strains grown in defined medium LD82 reached 2.0 × 10⁹ to 6.0 × 10⁹ CFU/ml of culture. All spiroplasma strains tested formed colonies readily on agar medium LD82. None of the spiroplasmas formed typical fried-egg colonies. All formed diffuse colonies, but the forms of colonies differed somewhat among the spiroplasma strains. In preliminary studies of nutritional requirements, phospholipids slightly enhanced the growth of the epiphytic and insect-pathogenic strains in medium LD82 and were found essential for good growth of S. citri.     

Customized media based on miniaturized screening improve growth rate and cell yield of methane-oxidizing bacteria of the genus Methylomonas

The growth of twelve methanotrophic strains within the genus Methylomonas, including the type strains of Methylomonas methanica and Methylomonas koyamae, was evaluated with 40 different variations of standard diluted nitrate mineral salts medium in 96-well microtiter plates. Unique profiles of growth preference were observed for each strain, showing a strong strain dependency for optimal growth conditions, especially with regards to the preferred concentration and nature of the nitrogen source. Based on the miniaturized screening results, a customized medium was designed for each strain, allowing the improvement of the growth of several strains in a batch setup, either by a reduction of the lag phase or by faster biomass accumulation. As such, the maintenance of fastidious strains could be facilitated while the growth of fast-growing Methylomonas strains could be further improved. Methylomonas sp. R-45378 displayed a 50 % increase in cell dry weight when grown in its customized medium and showed the lowest observed nitrogen and oxygen requirement of all tested strains. We demonstrate that the presented miniaturized approach for medium optimization is a simple tool allowing the quick generation of strain-specific growth preference data that can be applied downstream of an isolation campaign. This approach can also be applied as a first step in the search for strains with biotechnological potential, to facilitate cultivation of fastidious strains or to steer future isolation campaigns.     

Isolation and characterization of rhizosphere bacteria for the biocontrol of the damping-off disease of tomatoes in Tunisia

Fluorescent Pseudomonas spp., isolated from tomato and pepper plants rhizosphere soil, was evaluated in vitro as a potential antagonist of fungal pathogens. Pseudomonas strains were tested against the causal agents of tomatoes damping-off (Sclerotinia sclerotiorum), root rot (Fusarium solani), and causal agents of stem canker and leaf blight (Alternaria alternata). For this purpose, dual culture antagonism assays were carried out on 25% tryptic soy agar, King B medium and potato dextrose agar to determine the effect of the strains on mycelial growth of the pathogens. In addition, strains were screened for their ability to produce exoenzymes and siderophores. All the strains significantly inhibited Alternaria alternata, particularly in 25% TSA medium. Antagonistic effect on Sclerotinia sclerotiorum and Fusarium solani was greater on King B medium. Protease was produced by 30% of the strains, but no strain produced cellulase or chitinase. Finally, the selected Pseudomonas strain, Psf5, was evaluated on tomato seedling development and as a potential candidate for controlling tomato damping-off caused by Sclerotinia sclerotiorum, under growth chamber conditions. In vivo studies resulted in significant increases in plant stand as well as in root dry weight. Psf5 was able to establish and survive in tomato plants rhizosphere after 40 days following the planting of bacterized seeds.     

Utilization of Ammonia Nitrogen by Intestinal Bacteria Isolated from Pigs

In a medium containing ammonia, proteose peptone, and cysteine as nitrogen sources, 17 of 24 Bacteroidaceae strains, 3 of Selenomonas strains, 1 of 7 curved rods, 3 of 7 Spirochaetaceae strains, 8 of 20 Eubacterium strains, 8 of 13 Peptococcaceae strains, 3 of 4 Clostridium strains, 19 of 20 Enterobacteriaceae strains, and 1 of 8 Streptococcus strains utilized ammonia nitrogen preferentially to proteose peptone nitrogen. To determine the ability of intestinal microbes to synthesize amino acids from ammonia, ammonia utilization by Bacteroides ruminicola strain 9 was studied in defined media containing ammonia and other nitrogen sources. In another medium containing ammonia, proteose peptone, and cysteine as nitrogen sources, ammonia was preferentially utilized even when the proteose peptone nitrogen content was eight times greater than that of ammonia nitrogen. In a medium containing ammonia, an amino acid, and cysteine, the lowest uptake of ammonia nitrogen was observed when the medium contained aspartic acid, glutamic acid, threonine, or alanine; but ammonia was utilized more effectively than any of the amino acids. Incorporation of ¹⁵N from [¹⁵N]ammonia into bacterial amino acids was studied. ¹⁵N was incorporated into every amino acid of B. ruminicola strain 9, and the highest uptake was observed in aspartic acid and alanine.     

Isolation and characterization of bacteria capable of metabolizing lignin-derived low molecular weight compounds

Lignin, a major component of biomass, composed of homogeneous phenolic monomers and functions as a synthetic precursor in the production of specialty chemicals or polymers. In this study, bacterial strains that metabolize lignin-derived low molecular weight compounds (LLCs) were cultured which are capable of LLC bioconversion. We used an LLC mixture primarily composed of vanillin (VL), syringaldehyde (SA), vanillic acid (VA) and p-hydroxybenzoic acid which were prepared from a commercial alkaline lignin product. Enrichment culture was repeated twice in a medium containing the soil sample, the LLCs and inorganic salts. Three bacterial strains belonging to the genera Pseudomonas, Ochrobactrum, and Klebsiella were isolated. We found that only VL, SA, and VA were metabolized by the Pseudomonas strain, which was then found to grow in a medium with VL or VA as the sole source of carbon and energy. The VL isomers, namely, ovanillin and isovanillin were converted to the corresponding carboxylic acids but were not utilized as carbon sources by Pseudomonas. VL and VA are intermediates in the pathway of bacterial degradation of eugenol via ferulic acid. Several bacterial strains that metabolize VL, eugenol, and ferulic acid have been reported but such strains are rarely isolated from enrichment culture medium containing LLCs, due to insufficient induction by the precursors in the LLC medium. In this study, we demonstrated that the microorganisms involved in the bioconversion of LLCs can be isolated from simple enrichment culture.     

Classification of ethylene-producing bacteria in terms of biosynthetic pathways to ethylene

Two hundred and twenty-nine ethylene-producing strains of bacteria were identified among 757 bacterial strains which included 13 strains of chemolithotrophs. The ethylene-producing bacetria were classified into three groups, namely, l-methionine-dependent, 2-ketoglutarate-dependent and meat extract-dependent, with reference to their respective biosynthetic pathways to ethylene. Two hundred and twenty-five l-methionine-dependent strains were obtained, while the only 2-ketoglutarate-dependent strain was Pseudomonas syringae pv. phaseolicola PK2. Three strains of chemolithotrophs had ethylene-forming capacity, and Thiobacillus novellus IFO 12443 had a novel ethylene-forming system which was dependent upon the addition of meat extract into the culture medium. The ethylene-forming systems of two of the strains of Thiobacillus ferrooxidans have not yet been characterized. Several strains of non-ethylene-producing bacteria failed to produce ethylene, even when l-methionine was added to the culture medium. We examined the causes of their lack of ethylene-producing ability and judged that these strains are either NADH:Fe(III)EDTA oxidoreductase-less or methionine-uptake activity-less.     

Digestion of Herring by Indigenous Bacteria in the Minke Whale Forestomach

Northeastern Atlantic minke whales (Balaenoptera acutorostrata) have a multichambered stomach system which includes a nonglandular forestomach resembling that of ruminants. Bacteria from the forestomachs of herring-eating whales were enumerated and isolated in an anaerobic rumen-like culture medium (M8W medium). The total viable population of anaerobic bacteria ranged from 73 × 10⁷ to 145 × 10⁸/ml of forestomach fluid (n = 4). Lactobacillus spp. (19.7%), Streptococcus spp. (35.9%), and Ruminococcus spp. (12.8%) were the most common of the bacterial strains (n = 117) isolated by use of M8W medium from the forestomach fluid population of two minke whales. Most of the isolates stained gram positive (93.2%), 62.4% were cocci, and all strains were strictly anaerobic. The population of lipolytic bacteria in one animal, enumerated by use of a selective lipid medium, constituted 89.7% of the viable population. The total viable population of anaerobic bacteria in freshly caught and homogenized herring (Clupea harengus) ranged from 56.7 to 95.0 cells per gram of homogenized prey (n = 3) when M8W medium was used. Pediococcus spp. (30.6%) and Aerococcus spp. (25.0%) were most common of the bacterial strains (n = 72) isolated from the homogenized herring. Most of the bacterial strains were gram positive (80.6%), and 70.8% were cocci. Unlike the forestomach bacterial population, as many as 61.1% of the strains from the herring were facultatively anaerobic. All bacterial strains isolated from the prey had phenotypic patterns different from those of strains isolated from the dominant bacterial population in the forestomach, indicating that the forestomach microbiota is indigenous. Scanning electron microscopic examinations revealed large numbers of bacteria, surrounded by a glycocalyx, attached to partly digested food particles in the forestomach. These data support the hypothesis that symbiotic microbial digestion occurs in the forestomach and that the bacteria are indigenous to minke whales.     

Benomyl Tolerance of Ten Fungi Antagonistic to Plant-parasitic Nematodes

Ten strains of fungi were tested for tolerance to the fungicide benomyl. Verticillium chlamydosporium strain 2 did not grow in the presence of benomyl; Drechraeria coniospora strains 1 and 2 and Chaetomium sp. tolerated only 0.1 μg benomyl/ml medium; Acremonium bacillisporum, an unidentified fungus, and Phoma chrysanthemicola uniformly grew at 1 μg/ml, but some hyphae grew at higher benomyl concentrations; Fusarium sp. tolerated 475 μg/ml, but some hyphae grew on medium amended with 1,000 μg/ml; Verticillium lecanii and V. chlamydosporium strain 1 routinely tolerated 1,000 μg/ml. Fungi generally grew more slowly at higher than at lower benomyl concentrations. Strains with elevated tolerance to benomyl were selected from Acremonium bacillisporum, Drechmeria coniospora, Fusarium sp., and an unidentified fungus. These strains retained the increased tolerance after repeated transfers on unamended medium.     

Use of Aromatic Compounds for Growth and Isolation of Zoogloea

Nine Zoogloea strains, were examined for their ability to utilize 35 aromatic compounds. Benzoate, m-toluate, and p-toluate, as well as phenol, o-cresol, m-cresol, and p-cresol, were utilized by eight strains. These strains exhibited meta cleavage of catechol and of methyl-substituted catechols. With the exception of L-tyrosine, none of the aromatic compounds tested supported growth of Z. ramigera ATCC 19623. A medium containing sodium m-toluate was used to isolate 37 zoogloea-forming bacteria from various polluted environments. The isolates were identified as strains of Zoogloea.