Microbial Production of 4,4′-Dihydroxybiphenyl: Biphenyl Hydroxylation by Fungi

Of 15 species of fungi examined for their ability to hydroxylate biphenyl, 10 produced 4-hydroxybiphenyl. Seven of the 10 also produced 4,4′-dihydroxybiphenyl. The most efficient strains, Absidia pseudocylindrospora NRRL 2770 and Absidia sp. NRRL 1341, were more closely examined to determine their growth characteristics and the kinetics of biphenyl hydroxylation in batch fermentation. In the absence of biphenyl, A. pseudocylindrospora 2770 and Absidia sp. 1341 grew about as rapidly and efficiently in a defined glucose minimal medium as in a complex medium. Substrate yield coefficients for glucose in both media were 0.4 to 0.5 g of biomass per g of glucose, and the specific growth rate was about 0.17 h⁻¹ (doubling time, about 4 h). In this unoptimized system, 10 to 15 g of biomass per liter (dry weight) could be produced, using a defined salt solution and glucose as sole carbon and energy source. In the presence of biphenyl, growth was inhibited, more so for strain 1341 than for strain 2770. However, the specific activity for biphenyl hydroxylation (milligrams of biphenol per gram of biomass) was about 3.5 times greater for strain 1341. Furthermore, biphenyl hydroxylation appeared to require the presence of an oxidizable carbon and energy source (and perhaps growth) to proceed and, at least for strain 1341, hydroxylation seemed to be more efficient in the complex medium.     

Carbon Source Requirements for Exopolysaccharide Production by Lactobacillus casei CG11 and Partial Structure Analysis of the Polymer

Exopolysaccharide production by Lactobacillus casei CG11 was studied in basal minimum medium containing various carbon sources (galactose, glucose, lactose, sucrose, maltose, melibiose) at concentrations of 2, 5, 10, and 20 g/liter. L. casei CG11 produced exopolysaccharides in basal minimum medium containing each of the sugars tested; lactose and galactose were the poorest carbon sources, and glucose was by far the most efficient carbon source. Sugar concentrations had a marked effect on polymer yield. Plasmid-cured Muc^- derivatives grew better in the presence of glucose and attained slightly higher populations than the wild-type strain. The values obtained with lactose were considerably lower for both growth and exopolysaccharide yield. The level of specific polymer production per cell obtained with glucose was distinctively lower for Muc^- derivatives than for the Muc⁺ strain. The polymer produced by L. casei CG11 in the presence of glucose was different from that formed in the presence of lactose. The polysaccharide produced by L. casei CG11 in basal minimum medium containing 20 g of glucose per liter had an intrinsic viscosity of 1.13 dl/g. It was rich in glucose (76%), which was present mostly as 2- or 3-linked residues along with some 2,3 doubly substituted glucose units, and in rhamnose (21%), which was present as 2-linked or terminal rhamnose; traces of mannose and galactose were also present.     

Effect of the polysaccharide ofAgrobacterium radiobacter on the growth of plants and occurrence of damping-off in sugar beet

Agrobacterium radiobacter, strain B6 (a strain isolated in this laboratory, which limited the occurrence of damping-off of sugar beet and influenced growth of plants in hot-house and field experiments) was found to produce an acidic exopolysaccharide in a mineral medium with various carbon sources. Hydrolyzates of the polysaccharide contained glucose, galactose, glycerol, succinic acid and pyruvic acid, whose quantitative content varied according to the carbon source used. The polysaccharide isolated from the medium containing glucose exhibited the highest physiological activity. Seeds germinated best and sugar beet roots were found to grow most rapidly in a medium containing 0.2 % (W/W) of the polysaccharide. The roots exposed for 3 d in this medium grew 2.7-fold as compared with non-treated plants. Higher sumbers of microorganisms were detected on the surface of roots treated with the polysaccharide. Growth of roots was also stimulated when immersing the seeds (30 min) in a 0.2 –0.4 % solution of this polysaccharide. After a two-fold treatment the roots were less damaged by the fungusPythium ultimum. Plants from seeds treated with the polysaccharide grew in the field soil more rapidly than the non-treated plants but worse than after bacterization of the seeds byA. radiobacter B6 and were only partially protected against the damping-off of sugar beet.     

Diacetyl production and growth of Lactobacillus rhamnosus on multiple substrates

Lactobacillus rhamnosus is a heterolactic acid bacterium, which can be used to produce flavour compounds like diacetyl and acetoin. Various startegies have been applied to improve the growth rate and diacetyl yield. The use of multiple substrates affected growth as well as the yield of diacetyl. Growth on a medium containing glucose demonstrated a diauxic growth profile, with the second phase of growth being on the product, lactic acid. L. rhamnosus also grew on a medium containing citrate. Growth on medium containing glucose+citrate demonstrated simultaneous utilization of carbon sources. L. rhamnosus did not grow in a medium containing acetate and also did not co-metabolize it with glucose. Maximum specific growth rate ( _max) was found to increase in the case of simultaneous utilization of glucose+citrate (0.38 h^–1) as compared to glucose as the sole carbon source (0.28 h^–1). The yields of diacetyl were also found to increase for glucose + pyruvate and glucose + citrate (0.10 and 0.05 g g^–1 of glucose, respectively) as compared to glucose alone (0.01 g g^–1 of glucose). The productivity of diacetyl on medium containing glucose and citrate was double that of a medium containing only citrate, although the yields were comparable.     

Effect of growth substrates on morphology of Nocardia corallina

Cells of Nocardia corallina ATCC 4273 form multiply branched coenocytic mycelia and subsequent fragment to spherical cells when grown on solidified complex media. In liquid shake cultures using complex media the organisms grow into pleomorphic but seldomly branched rods, divide as rods and then the rods fragment to spheres as the stationary phase is reached. In a defined liquid medium with glucose as carbon source, the organisms divide entively as spheres at a doubling time of 44 hrs. The addition of l-tyrosine, some fatty acids and tricarboxylic acid cycle intermediates or fructose to the glucose medium caused the cells to grow at considerably faster growth rates (2.8–8.5 hrs doubling times) and to undergo the sphere-rod-sphere growth cycle. Other amino acids, fatty acids or sugars added singly to the glucose medium did not produce the sphere to rod morphology change. Some amino acids when added to the medium in pairs effected sphere to rod morphopoiesis. None of these amino acids alone were effectors. Some of the culture grew as rods and the remainder as spheres when isoleucine and valine were added to the glucose medium. No other amino acid combination tested gave this result. The reason for the mixed growth response was traced to inhomogeneity of the parent culture. The life cycle of N. corallina is illustrated in a series of photomicrographs of two slide cultures.     

GLUCOSE FERMENTATION AND GROWTH OF SELENOMONAS SPUTIGENA ON A MINIMAL MEDIUM

Very little is known about the growth physiology and metabolic niche of the human oral isolate Selenomonas sputigena. The objective of this study was to devise a minimal medium for comparing growth rates and fermentation of rumen Selenomonas ruminantium strains with S. sputigena. When anaerobically grown on a minimal glucose medium containing yeast extract as the only chemically undefined component, S. sputigena produced acetate, propionate, and succinate while S. ruminantium strains produced primarily lactate. When strains were compared (P < 0.05) for each carbon source that yielded growth, rumen strain HD₄ grew faster than all other strains on glucose, cellobiose and glycerol while strain GA192 grew faster on trehalose. Rumen strains GA192, PC18, and HD₄ grew faster on mannitol than rumen strains D and GA31. S. sputigena grew faster on lactate (0.38 ± 0.04) than any of the S. ruminantium strains. The minimal medium developed in this study should be useful for jurmer physiological studies on fermentation and metabolism in S. sputigena.     

Effect of Light on Glucose Utilization by Euglena gracilis

The effect of light on glucose consumption by wild-type Euglena gracilis Z. and mutant cells has been studied. When dark- or light-grown wild-type cells are transferred from a medium containing sodium butyrate as the only carbon source to a glucose-containing medium, glucose consumption is blocked for 6 to 7 days when cultures are incubated under a light intensity of at least 600 lux. During this time cells multiply at the same rate as controls kept on media devoid of any utilizable organic carbon source. This light-induced inhibition of glucose consumption and of growth on glucose-containing medium is not related to photosynthesis since: (a) glucose consumption is inhibited by light intensities much lower than those required for high phototrophic growth; (b) the inhibition of photosynthesis by 3-(3,4-dichlorophenyl)-1, 1-dimethylurea does not overcome the inhibition of glucose consumption; and (c) nonphototrophic-growing mutants also show light-induced inhibition of glucose consumption and of growth on glucose-containing medium. This inhibition of growth by light might be explained by modification in the permeability of the cellular membrane.     

Production of Proteinase on Noncarbohydrate Carbon Sources by Pseudomonas aeruginosa

Proteinase production by Pseudomonas aeruginosa was studied in medium containing noncarbohydrate materials, especially various hydrocarbons, as the sole carbon source. On heavy oil, kerosene, n-paraffinic hydrocarbon of C₁₂, C₁₄, or C₁₆, and propylene glycol, the bacteria grew well and high protinase production was observed. However, production on paraffinic hydrocarbon differed remarkably with strains of varied origins. The elastase-positive strain, IFO 3455, showed abundant growth and high proteinase production on medium containing a paraffin of C₁₂, C₁₄, or C₁₆, whereas the elastase-negative strain, IFO 3080, showed little growth on the same medium. Neither elastase-positive nor elastase-negative strains, however, utilized n-paraffins of C₅ to C₁₀, or various aromatic hydrocarbons such as benzene, naphthalene, phenanthrene, and anthracene. The proteinases produced on the noncarbohydrate medium were identical with those produced in glucose medium.     

Diauxic growth of Penicillium camembertii on glucose and arginine

The growth of Penicillium camembertii during batch culture in a synthetic medium containing glucose and arginine was examined. The diauxic growth observed can be well characterized. Indeed, in a first phase, glucose and arginine were, respectively, assimilated as carbon and nitrogen sources, with an acidification of the medium (until 3.5), since arginine was taken up in exchange for protons. During this phase of growth, arginine, in addition to glucose, was also assimilated as an energy source, resulting in the release of the arginine carbon content as CO₂. Then, in a second phase, characterized by reduced growth rates after glucose depletion, arginine was assimilated as a carbon and nitrogen source, as well as an energy source, resulting in ammonium release which raised the pH (final pH 6.3), despite the amino acid/H⁺ exchange, since amino acids contain excess nitrogen in relation to their carbon content for fungi.     

Nutritional requirements ofXanthomonas phaseoli var.fuscans

As found by Starr (1946),l-glutamic acid is necessary for the growth ofXanthomonas phaseoli var.fuscans. According to our results, the growth is stimulated byl-asparagine in the presence ofl-glutamic acid;l-asparagine itself, however, does not serve as a source of carbon and nitrogen.Xanthomonas phaseoli var.fuscans grew well in a medium containing tryptone. Some peptides of the acidic fraction isolated from tryptone affected the growth as much as tryptone itself. Vitamins and plant growth substances did not affect the growth of the bacteria; proteins appeared to be a poor carbon and nitrogen source. On substituting glucose in a glutamic acid-containing medium with another saccharide, the growth of the bacteria was found equal or better in media containing mannose, sucrose, fructose, maltose or starch. The bacteria grew less satisfactorily in media containing galactose and cellobiose as compared with media containing glucose.     

Organic or mineral nitrogen source during Penicillium camembertii growth on a glucose limited medium

Penicillium camembertii was cultivated on a carbon-limited medium (glucose). Two nitrogen sources were compared, a mineral, ammonium, and an organic nitrogen source, lysine. Among the amino acids convenient nitrogen sources for P. camembertii, lysine was chosen since it cannot be assimilated as a carbon source for cell biosynthesis. During culture on glucose and ammonium, a decline phase immediately followed growth after glucose depletion, since no energy source remained in the medium. On the contrary, on glucose and lysine, a stationary state was recorded after glucose depletion, since lysine was used as the energy supply for cell maintenance, leading to the release of the corresponding carbon as CO₂, while nitrogen from lysine was released as ammonium.     

Nutrition of Acetobacter rancens S3 and F11 Isolated from Tanks for Vinegar Production

The strains S3 and F11 which were isolated respectively from static and submerged tanks for vinegar production were identified as Acetobacter rancens. Neither strain grew in an ammonium defined medium containing ethanol, glucose, glycerol or organic acids as the sole carbon source. When casamino acids were added, they grew luxuriantly with lactate, ethanol or glycerol as the carbon source and less well with acetate or glucose. They grew, forming much acetic acid, in defined ethanol medium when alanine was supplied in place of casamino acids, but strain S3 showed a longer lag time than strain Fl1. This lag time could be shortened by addition of aspartate and glutamate. These amino acids could be replaced by succinate, fumarate, malate, lactate, pyruvate or propionate but not by glucose. Both strains required lactate or pyruvate in defined glucose medium but many other organic acids, which were effective in defined ethanol medium, were ineffective or slightly effective in glucose medium.     

Degradation of 2,3-Diethyl-5-Methylpyrazine by a Newly Discovered Bacterium, Mycobacterium sp. Strain DM-11

A bacterium was isolated from the waste gas treatment plant at a fishmeal processing company on the basis of its capacity to use 2,3-diethyl-5-methylpyrazine (DM) as a sole carbon and energy source. The strain, designated strain DM-11, grew optimally at 25°C and had a doubling time of 29.2 h. The strain did not grow on complex media like tryptic soy broth, Luria-Bertani broth, or nutrient broth or on simple carbon sources like glucose, acetate, oxoglutarate, succinate, or citrate. Only on Löwenstein-Jensen medium was growth observed. The 16S rRNA gene sequence of strain DM-11 showed the highest similarity (96.2%) to Mycobacterium poriferae strain ATCC 35087^T. Therefore, strain DM-11 merits recognition as a novel species within the genus Mycobacterium. DM also served as a sole nitrogen source for the growth of strain DM-11. The degradation of DM by strain DM-11 requires molecular oxygen. The first intermediate was identified as 5,6-diethyl-2-hydroxy-3-methylpyrazine (DHM). Its disappearance was accompanied by the release of ammonium into the culture medium. No other metabolite was detected. We conclude that ring fission occurred directly after the formation of DHM and ammonium was eliminated after ring cleavage. Molecular oxygen was essential for the degradation of DHM. The expression of enzymes involved in the degradation of DM and DHM was regulated. Only cells induced by DM or DHM converted these compounds. Strain DM-11 also grew on 2-ethyl-5(6)-methylpyrazine (EMP) and 2,3,5-trimethylpyrazine (TMP) as a sole carbon, nitrogen, and energy source. In addition, the strain converted many pyrazines found in the waste gases of food industries cometabolically.     

Selection and characterization of acriflavine-induced mutants of Candida albicans

Acriflavine-treated cells of C. albicans plated on a medium containing glucose as the principal carbon source gave rise to numerous colonies, most of which grew when replica-plated onto a similar medium containing sodium acetate substituted for glucose. Of the small fraction of colonies from the glucose medium which failed to replicate, some were found to be true petites, deficient for cytochromes a and b; others possessed complete cytochrome spectra, like those of their wild-type parents, but, nevertheless, respired at reduced rates on both fermentable and non-fermentable substrates. The role of the conventional cytochrome system in a wild-type culture was indicated by the strong inhibition of its respiration by cyanide, azide and antimycin A.     

Ability of ectomycorrhizal fungi to utilize starch and related substrates

Basidiomycetous fungi of 55 strains of 33 species in 15 genera which are thought to be ectomycorrhizal were grown on starch and related substrates as a sole carbon source, and their ability to utilize these substrates was determined. Mycellial weights of the fungi grown on agar media containing starch and amylose varied between the strains from 1.1 to 94.9 mg/flask and from 0.4 to 93.3mg/flask, respectively. Mycelial growth rates ranged from 0 to 1.17 mm/d on barley grain medium and from 0 to 2.03 mm/d on rice grain medium; the highest rate corresponded to about half of the average of reference wood-rotting fungi. Most of the mycorrhizal fungi that grew well on amylose gave higher growth rates on barley. Several strains inLyophyllum, Hebeloma, Sarcodon, andTricholoma grew well on both glucose and starch media.     

Erythritol as a Selective Substrate for the Growth of Serratia marcescens

Serratia marcescens grew on a basal medium containing 0.5% erythritol as sole source of carbon for growth and energy. Only an occasional strain of Enterobacter aerogenes among several members of the family Enterobacteriaceae were able to utilize erythritol.     

Lovastatin Biosynthesis by Aspergillus terreus in a Chemically Defined Medium

Lovastatin is a secondary metabolite produced by Aspergillus terreus. A chemically defined medium was developed in order to investigate the influence of carbon and nitrogen sources on lovastatin biosynthesis. Among several organic and inorganic defined nitrogen sources metabolized by A. terreus, glutamate and histidine gave the highest lovastatin biosynthesis level. For cultures on glucose and glutamate, lovastatin synthesis initiated when glucose consumption levelled off. When A. terreus was grown on lactose, lovastatin production initiated in the presence of residual lactose. Experimental results showed that carbon source starvation is required in addition to relief of glucose repression, while glutamate did not repress biosynthesis. A threefold-higher specific productivity was found with the defined medium on glucose and glutamate, compared to growth on complex medium with glucose, peptonized milk, and yeast extract.     

Amino Acid Production by Submerged Cultivation ofPseudomonas fluorescens on Gasoline

During our screening program for hydrocarbon-degrading microorganismsPseudomonas fluorescens was isolated that grew on gasoline as the sole source of carbon and energy. During growth on gasoline it produced proline and tryptophan. Among the nitrogen salts tested, ammonium sodium hydrogen orthophosphate supported maximum amino acid production and growth. By optimizing the medium components a two-fold increase in proline and tryptophan production was achieved.     

Time course of adaptation to elevated salt by Saccharomyces rouxii

Cells from a 24-h preculture of Saccharomyces rouxii grew without lag on a medium containing yeast extract, neopeptone, and glucose. Additions of 0.3 M KCl or 0.6 M pentaerythritol, which increased the osmolality of the medium 10-fold, still allowed immediate growth, whereas addition of 0.3 M NaCl resulted in a lag of 23 h (after which the growth rate was normal). The time course of growth in this elevated-sodium medium of 0.3 M was studied under defined conditions for inoculum history as well as experimental culture. S. rouxii cells with single exposure to elevated-sodium medium for 23 h exhibited a shorter lag (12 h) on fresh elevated-sodium medium; even with an intervening washing step. Elevated-sodium medium that had received the standard inoculum became conditioned during the lag so that it then supported growth of new, untrained cells with only 2 h lag; even with an intervening filter- or heat-sterilization treatment. The lag period on elevated-sodium medium could also be decreased by (1) using younger cells for inoculum, (2) increasing the amount of the inoculum, or (3) adding extra glucose to the medium. The results indicate that a diffusible, heat-stable factor is synthesized by cells during adaptation to elevated sodium, and that a threshold concentration of the factor is a prerequisite for the normal growth that eventually ensues. A change in retentivity for the factor with cellular age may explain the different growth kinetics with younger or older inocula.     

Nutritional requirements of some non-pathogenic Neisseria grown in simple synthetic media.

Ten species of non-pathogenic Neisseria were grown in simple defined liquid media containing amino acids, biotin, nicotinic acid, calcium pantothenate, ferrous sulfate, magnesium sulfate, and potassium phosphate. Two of these Neisseria were induced to grow with glutamic acid as the carbon and nitrogen source. The remaining eight Neisseria grew in glutamic acid medium supplemented with from one to four additional amino acids, lactate, or lactate and glucose. A strain of N. flavescens grew in the absence of added growth factors whereas the remaining nine species of Neisseria required either biotin or nicotinic acid; pantothenate was required by two and was stimulatory for three of these species. Use of carbohydrates by the non-pathogenic Neisseria in synthetic medium was tested. Two strains failed to use any of the 14 carbohydrates tested; one strain used only glucose; the remaining seven strains used fructose, glucose, maltose, and sucrose to varying degrees.