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.     

Carbon and nitrogen yields during batch cultures of Geotrichum candidum and Penicillium camembertii

Batch cultures of Geotrichum candidum and Penicillium camembertii were carried out on peptones as carbon and nitrogen source and in the presence of lactate as a second carbon source. Unless growth ceased, carbon and nitrogen yields remained constants, except yields involving lactate consumption by G. candidum, since this fungus preferentially metabolized peptones as a carbon source. For both fungi, nearly 40% of the available carbon was metabolized for cellular biosynthesis and the remainder (about 60%) as carbon dioxide, for the energy supply of both biosynthesis and viable cell maintenance. Moreover, in relation to their carbon content, amino acids contain excess nitrogen, which was released as ammonium. From all these, the yields of ammonium nitrogen on cellular nitrogen were in all cases higher than 1, and were especially high when the medium contained only peptones as a carbon source, 4.4 and 5.7 for G. candidum and P. camembertii respectively. Indeed, in this case, the excess nitrogen was especially pronounced.     

Effects of Nitrogen Sources on Cellulose and Synthetic Lignin Degradation by Phanerochaete chrysosporium

Phanerochaete chrysosporium degraded cellulose faster with organic nitrogen sources than with NH₄Cl. Simple and complex nitrogen sources added at the time of inoculation to N-limited cultures of P. chrysosporium, with glucose as carbon/energy source, transiently stimulated degradation of synthetic [¹⁴C]lignin to ¹⁴CO₂. The same nitrogen sources added 5 days after inoculation, when the cultures were entering secondary metabolism, delayed ¹⁴CO₂ production. The various N sources affected synthetic lignin degradation in defined medium differently than lignin degradation in aspen wood.     

The influence of various carbon and nitrogen sources on oil production byFusarium oxysporum

The oil-synthesizing capacityof Fusarium oxysporum, cultivated on basal nutrient medium, was evaluated using different carbon and nitrogen sources. In one of the media, molasses was also used as a principal carbon source. Media containing glucose and ammonium nitrate were found to be most efficient for oil production. Fatty acid profile of the fungal oil indicated the presence of a wide range of fatty acids ranging from C₈ to C₂₄. Fatty acid composition largely depends on the type of carbon and nitrogen sources.     

Optimization of culture conditions and properties of lipase from Penicillium camembertii Thom PG-3

The culture medium including nitrogen source, carbon source and metal ions, for lipase from Penicillium camembertii Thom PG-3 was optimized and the optimal medium consisted of soybean meal (fat free) 4%, Jojoba oil 0.5%, (NH₄)₂HPO₄, 0.1% Tween 60, initial pH 6.4 and the inoculation was at 28 °C for 96 h. The lipase activity produced was enhanced 3.9-fold and reached 500 U/ml. The lipase was purified 19.8-fold by pH precipitation, ethanol precipitation and ammonium sulphate precipitation as well as DEAE-cellulose chromatography. The purified lipase showed one polypeptide band in SDS-polyacrylamide gel electrophoreses (SDS-PAGE) with molecular weight 28.18 kDa. The optimal pH and temperature for activity of lipase were 6.4 and 48 °C, respectively, which are higher than those lipases from other penicillium sources. The P. camembertii Thom lipase is 1,3-positional specificity for hydrolysis of triglyceride and hydrolyses plant oil preferentially to animal oil. The lipase can be used in short chain ester synthesis with an esterification degree of 95%.     

Influence of cultivation conditions on production of lignocellulolytic enzymes by Ceriporiopsis subvermispora

The aim of this work was to make a survey describing factors that influence the production of extracellular enzymes by white-rot fungus Ceriporiopsis subvermispora responsible for the degradation of lignocellulolytic materials. These factors were: carbon sources (glucose, cellulose, hemicellulose, lignin, maltose and starch), nitrogen sources (ammonium sulphate, potassium nitrate, urea, albumin and peptone), pH, temperature and addition of three different concentrations of Cu²⁺ and Mn²⁺. The cellulase and xylanase activities were similar in medium with different carbon sources and the highest cellulase and xylanase activities were measured in medium with urea and potassium nitrate as nitrogen sources, respectively. The highest laccase activity was observed in medium with lignin and peptone as carbon and nitrogen sources. In other experiments, time course of production of lignocellulolytic enzymes by white-rot fungus C. subvermispora in medium with lignin or glucose as carbon sources was observed.     

The effect of different nitrogen and carbon sources on amino acid synthesis in Ulva,Dictyota and Pterocladia

Summary This investigation includes a study of the effect of ammonium salt, nitrate and urea as nitrogen sources; vitamin B₆ as cofactor in transamination, and of acetate, pyruvate and glucose as carbon sources on the dry weight, total nitrogen and amino acid synthesis in Ulva, Dictyota and Pterocladia. The results showed that urea and to a lesser extent ammonium salt were better nitrogen sources for either Ulva or Pterocladia, while ammonium salt was best for Dictyota. Vitamin B₆ was effective in transaminations and resynthesis of amino acids in the three marine algae, especially Ulva. Pyruvate was a better carbon source than either acetate or glucose in increasing dry weights, total nitrogen and amino acid synthesis in Ulva and Dictyota, whereas acetate was best in Pterocladia.     

A comparison of growth rate of algae as influenced by variation in nitrogen nutrition inChlorella pyrenoidosa andScenedesmus obliquus

Algae were cultivated in nutrient solutions containing nitrates or ammonium salts as the nitrogen source. We measured the culture density in the case of autotrophic and mixotrophic cultivation at different pH values, in the presence of nitrate also at different concentrations and in the absence of molybdenum. The dry weight and amount of nitrogen in the cells under these conditions were determined. According to results obtained we conclude thatChlorella, in contrast toScenedesmus, prefers ammonia as the nitrogen source in the first growth period, later both prefer nitrogen from nitrates. Nitrogen from ammonium salts has a positive effect only during short-time cultivation. If glucose was used as a mixotrophic energy source (or perhaps H-donor), the unsuitability of ammonia as a nitrogen source was more marked. We suppose that the lower growth intensity of older cultures (i.e., after seven days) in ammonia medium is the result of the use of endogenous energy sources. Both algae have adaptive systems making it possible to use nitrate nitrogen even in the absence of molybdate.     

Physiological parameters of growth in Saprolegnia parasitica coker

Persistent bacteria were separated fromS. parasitica by means of the oligodynamic effect of a silver ring in a modification ofRaper's technique. Inoculation of fungal cultures was by means of mycelial macerate. Growth was measured by mycelial dry weight. A chemically defined medium (standard medium) was developed which consisted of a mineral base (chlorides of magnesium, manganese, zinc, calcium, and iron) chelated with EDTA, supplemented with glucose, sodium glutamate, and methionine, and buffered at pH 7.0 with 0.01 M. KH₂PO₄. Shaking culture methods supported increased growth rates and higher dry weight yields compared to stationary methods. Excellent growth occurred between 15 to 30°C. in the standard medium and between pH 4.0 and 8.0 in the standard medium plus 0.01 M. sodium succinate and 0.01 M. TRIS used as additional buffers. Significant phosphate toxicity was demonstrated at concentrations exceeding 0.05 M. Sodium succinate and TRIS, used as buffers at 0.01 M. each, were compatible withS. parasitica, whereas boric acid, sodium barbital, and sodium citrate inhibited growth under similar conditions. Substitution of other carbon sources for glucose in the standard medium (on an equal carbon basis where possible) indicated that cellobiose, dextrin, fructose, glycerine, glycogen, sodium lactate, and soluble starch supported significantly heavier growth than did the standard medium minus glucose; glycogen had a greater yield than did the standard medium minus glucose; glycogen had a greater yield than the standard medium. Arabinose, dulcitol, galactose, inulin, lactose, mannitol, mannose, raffinose, rhamnose, sorbitol, sucrose, and xylose neither stimulated nor inhibited growth; however, growth inhibition was produced by α-ketoglutaric acid, sodium citrate, and sodium succinate. When fatty acids and lipids were substituted for glucose (on an equal carbon basis where possible), only butter, lard, oleo, and palmitic acid supported heavier growth ofS. parasitica than the standard medium minus glucose. Stearicacid neither stimulated nor inhibited growth; acetic acid, butyric acid, formic acid, octanoic acid, and propionic acid significantly inhibited the growth of the fungus. Various nitrogen sources were substituted for sodium glutamate in the standard medium (on an equal nitrogen basis where possible). Casein hydrolysate and gelatin produced yields higher than that developed in the standard medium; other nitrogen sources produced lesser yields but still greater than those from the standard medium minus sodium glutamate:

1. Alanine, arginine, aspartic acid, and histidine (good nitrogen sources).
2. Ammonium chloride, cysteine, leucine, serine, and urea (fair nitrogen sources).
3. Glycine, isoleucine, lysine, methionine, phenylalanine, potassium nitrate, sodium nitrate, threonine, tryptophan, and valine (poor nitrogen sources).

When various sulfur sources were substituted for methionine in the standard medium (on an equal sulfur basis), only cysteine and cystine produced dry weights comparable to that which developed in the standard medium. The following were very poor sulfur sources yet supported more growth than did the standard medium minus methionine: sodium sulfide, sodium thiosulfate, and thiourea. The ability of the other sulfur sources to support growth was questionable: potassium persulfate, sodium bisulfite, sodium dithionate, sodium hydrosulfite, sodium sulfate, sodium sulfite, and sodium thiocyanate. The standard medium contained only two nitrogen sources: sodium glutamate and methionine. Sodium glutamate served as a carbon source as well as a nitrogen source, but methionine could serve only as a source of sulfur.     

Nutritional studies on Colletotrichum gloeosporioides Penz

Summary Colletotrichum gloeosporioides isolated from the diseased leaves ofPolyscias balfuriana could grow and sporulate on a wide range of pH (viz. from 3.0 to 9.0). Maximum growth was recorded at pH 5.5. Mannitol was the best carbon source for growth. Good growth as well as good or excellent sporulation was also recorded on glucose, fructose, maltose and starch. Organic acids (malic and tartaric) supported poor growth.Present organism could utilize a number of nitrogen sources. Nitrates in general were comparatively better sources than ammonium compounds. Aspartic acid was found to be the best nitrogen source for growth. Nitrites were toxic at lower pH values though they supported growth at alkaline medium. Best growth of the organism was obtained on MgSO₄, 7H₂O. The urea supported poor growth. ZnSO₄ inhibited the growth completely. The present organism was incapable of growing in media lacking carbon, nitrogen or sulphur.     

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.     

Biodegradation of p-nitrophenol by Pseudomonas aeruginosa HS-D38 and analysis of metabolites with HPLC–ESI/MS

Pseudomonas aeruginosa strain HS-D38 was capable of mineralizing p-nitrophenol (PNP) as the sole source of carbon, nitrogen and energy. Degradation of 200 mg L^?1 PNP was examined in different media including: (i) MSM (mineral salts medium, no carbon and nitrogen source); (ii) addition of 1% ammonium chloride as additional nitrogen source (ANM); and (iii) addition of 1% glucose as a carbon source (ACM). Complete degradation of 200 mg L^?1 PNP was achieved in 12 h in MSM. Additional ammonium chloride accelerated the PNP degradation, but additional glucose inhibited this process. This strain metabolized as high concentration as 300 and 500 mg L^?1 of PNP in 14 h and 24 h, respectively, in MSM. The degradation was accompanied by release of stoichiometric amount of nitrate from PNP. During the bacterial growth on PNP, hydroquinone and 1,2,4-benzenetriol were observed as the key degradation intermediates by using a combination of techniques, including HPLC–DAD and LC–ESI/MS compared with the authentic standards. These results indicated that PNP was degraded via a hydroquinone pathway.     

Shigella dysenteriae 60R strain adheres to and invades tissue culture cells in the absence of virulence plasmid

The influence of various carbon and nitrogen sources on fusarin C synthesis was examined in submerged cultures of Fusarium moniliforme NRRL 13616. Using a zinc-deficient, synthetic medium, highest levels of fusarin C were produced by cultures grown with urea or ammonium sulfate as the nitrogen source and fructose, sucrose, or glucose as the carbon source. In media supplemented with various concentrations of glucose and ammonium sulfate, glucose concentrations which provided excess carbohydrate significantly increased fusarin C synthesis, regardless of the ammonium sulfate concentration.     

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.     

Components of fermentation medium regulate bacteriocin synthesis by the recombinant strain Lactococcus lactis subsp. lactis F-116

The regulation of the synthesis of bacteriocin produced by the recombinant strain Lactococcus lactis subsp. lactis F-116 has been studied. The synthesis is regulated by the components of the fermentation medium, the content of inorganic phosphate (KH₂PO₄), yeast autolysate (source of amine nitrogen), and changes in carbohydrates and amino acids. The strain was obtained by fusion of protoplasts derived from two related L. lactis subsp. lactis strains, both exhibiting a weak ability to synthesize the bacteriocin nisin. Decreasing the content of KH₂PO₄ from 2.0 to 1.0 or 0.5% caused bacteriocin production to go down from 4100 to 2800 or 1150 IU/ml, respectively; the base fermentation medium contained 1.0% glucose, 0.2% NaCl, 0.02% MgSO₄, and yeast autolysate (an amount corresponding to 35 mg % ammonium nitrogen). The substitution of sucrose for glucose (as the source of carbon) increased the antibiotic activity by 26%, and the addition of isoleucine, by 28.5%. Elevation of the concentration of yeast autolysate in the low-phosphate fermentation medium stimulated both the growth of the lactococci and the synthesis of bacteriocin. Introduction of 1% KH₂PO₄, yeast autolysate (an amount corresponding to 70 mg % ammonium nitrogen), 2.0% sucrose, and 0.1% isoleucine increased the bacteriocin-producing activity of the strain by 2.4 times.     

Photosynthetic Assimilation of NO(3) by Intact Cells of the Cyanobacterium Anacystis nidulans: Influence of NO(3) and NH(4) Assimilation on CO(2) Fixation

Illuminated suspensions of Anacystis nidulans, supplied with saturating concentrations of CO₂ evolved O₂ at a greater rate when nitrate was simultaneously present. The extent of the stimulation of noncyclic electron flow induced by nitrate was dependent on light intensity, being maximal under light saturating conditions. Accordingly, nitrate depressed the rate of CO₂ fixation at limiting but not at saturating light, this depression reflecting the competition between both processes for assimilatory power. In contrast, ammonium stimulated CO₂ fixation at any light intensity assayed, the stimulation being dependent on the incorporation of ammonium to carbon skeletons. The positive effect of ammonium on CO₂ fixation also appeared to occur when nitrate was the nitrogen source, since with either nitrogen source an increase in the incorporation of newly fixed carbon into acid-soluble metabolites took place. From these results, the in vivo partitioning of assimilatory power between photosynthetic nitrogen and carbon assimilation and the quantitative and qualitative effects of inorganic nitrogen assimilation on CO₂ fixation are discussed.     

Production of polyesters consisting of medium chain length 3-hydroxyalkanoic acids by Pseudomonas mendocina 0806 from various carbon sources

Pseudomonas mendocina strain 0806 was isolated from oil-contaminated soil and found to produce polyesters consisting of medium chain length 3-hydroxyalkanoates (mclPHAs). The monomers of mclPHAs contained even numbers of carbon atoms, such as 3-hydroxyhexanoate (HHx or C₆), 3-hydroxyoctanoate (HO or C₈), and/or 3-hydroxydecanoate (HD or C₁₀) as major components when grown on many carbon sources unrelated to their monomeric structures, such as glucose, citric acid, and carbon sources related to their monomeric structures, such as myristic acid, octanoate, or oleic acid. On the other hand, PHA containing both even and odd numbers of hydroxyalkanoates (HA) monomers was synthesized when the strain was grown on tridecanoic acid. The molar ratio of carbon to nitrogen (C/N) had a significant effect on PHA composition: the strain produced PHAs containing 97–99% of HD monomer when grown in a glucose ammonium sulfate medium of C/N<20, and 20% HO, and 80% of the HD monomer when growth was conducted in media containing C/N>40. It was demonstrated that the HO/HD ratio in the polymers remained constant in media with a constant C/N ratio, regardless of the glucose concentration. Up to 3.6 g/L cell dry weight containing 45% of PHAs was produced when the strain was grown for 48 h in a medium containing 20 g/L glucose with a C/N ratio of 40.     

Lysine catabolism inStreptomyces ambofaciens producer of macrolide antibiotic,spiramycin

Spiramycin production was highly stimulated when lysine was used as the sole nitrogen source. This amino acid was catabolized by the -transaminase pathway characterized by dosage of cadaverine aminotransferase (CAT) enzyme. The Km_cadaverine was of 57mM. CAT was highly induced by lysine (634% in comparison with ammonium). Addition of 40mm of ammonium in a culture begun with 20mm of lysine as the sole initial nitrogen source repressed CAT biosynthesis by 24% but did not affect spiramycin production seriously. Addition of 20mm of lysine in a culture started with 40mm ammonium induced CAT biosynthesis of 425%, but did not allow spiramycin production. In these two cases, spiramycin production seems to be conditioned by the nitrogen source initially present in the culture medium. CAT activity was inhibited by ammonium ions (33% at 20mm), whereas lysine had no effects.     

Isolation and characterization of a furfural degrading sulfate-reducing bacterium from an anaerobic digester

A sulfate-reducing bacterium (SRB) was isolated from a continuous anaerobic digester, which converted the furfural-containing wastewater to methane and CO₂. This SRB isolate could use furfural, furfuryl alcohol, and 2-furoic acid as sole source of carbon and energy in a defined mineral sulfate medium. Acetic acid was the major end product of furfural degradation. This organism also used wide varieties of other carbon sources, including ethanol, pyruvate, lactate, succinate, propanol, formate, and malate. The SRB isolate contained the electron carrier desulfoviridin. It used SO₄, NO₃, and thiosulfate as electron acceptors. This isolate used ammonium chloride, nitrate and glutamate as nitrogen source. The characteristics of the SRB isolate were closely similar toDesulfovibrio sp.