Effect of the carbon source on biosurfactant production byPseudomonas aeruginosa 44T1

Summary Pseudomonas aeruginosa 44T1 produces rhamnolipids when grown on C₁₂ n-alkane but not with other hydrocarbons tested. Best results were obtained with olive oil as carbon source; a final production of 7.65 g rhamnolipid/l with a production yield of 38.2% was detected.     

The effect of nitrogen and carbon sources on proteinase production by Pseudomonas fluorescens

Some factors influencing the production of an extracellular proteinase by Pseudomonas fluorescens NCDO 2085 were studied. Proteinase production was optimal at 20 degrees C and pH 6.9 in static culture when calcium was included in the medium. Proteinase was not detectable in basal medium but could be induced by organic nitrogen compounds. The proteinase was produced in the exponential phase of growth on protein substrates but not until early stationary phase during growth on amino acids. The organism did not utilize lactose, the most abundant carbohydrate in milk. Citrate was readily utilized as an energy source but had a strong repressive effect on proteinase production. A medium containing sodium caseinate and pyruvate supported good growth and enzyme production. All the amino acids utilized as a sole carbon source, with the exception of serine, could induce proteinase production. Asparagine was the most effective amino acid inducer. Particular combinations of amino acids could induce or repress proteinase production. The regulation of proteinase production by Ps. fluorescens NCDO 2085 appears to be based on a balance between induction by low concentrations of low molecular weight degradation products and sensitivity to end product catabolite repression. The results suggest that the function of the proteinase is to ensure a supply of carbon rather than amino acids for protein synthesis.     

The effect of nitrogen and carbon sources on proteinase production by Pseudomonas fluorescens

Some factors influencing the production of an extracellular proteinase by Pseudomonas fluorescens NCDO 2085 were studied. Proteinase production was optimal at 20C and pH 69 in static culture when calcium was included in the medium. Proteinase was not detectable in basal medium but could be induced by organic nitrogen compounds. The proteinase was produced in the exponential phase of growth on protein substrates but not until early stationary phase during growth on amino acids. The organism did not utilize lactose, the most abundant carbohydrate in milk. Citrate was readily utilized as an energy source but had a strong repressive effect on proteinase production. A medium containing sodium caseinate and pyruvate supported good growth and enzyme production. All the amino acids utilized as a sole carbon source, with the exception of serine, could induce proteinase production. Asparagine was the most effective amino acid inducer. Particular combinations of amino acids could induce or repress proteinase production. The regulation of proteinase production by Ps. fluorescens NCDO 2085 appears to be based on a balance between induction by low concentrations of low molecular weight degradation products and sensitivity to end product catabolite repression. The results suggest that the function of the proteinase is to ensure a supply of carbon rather than amino acids for protein synthesis.     

Effect of carbon and nitrogen sources on glucoamylase production inLactobacillus brevis

A strain ofLactobacillus brevis produced extracellular glucoamylase. Induction of the glucoamylase occurred when saccharides such as starch, dextrin, maltose, mannitol and sucrose were employed as sole carbon sources. Synthesis of the amylase also occurred when soybean extract and peptone were used as sole nitrogen sources. The organism could be employed as a starter culture for local food fermentation.     

Effects of carbon and nitrogen sources on the proteome of Pseudomonas aeruginosa PA1 during rhamnolipid production

The PA1 strain of Pseudomonas aeruginosa isolated from oil waste produces rhamnolipid, a biodegradable surfactant with applications in several industrial and environmental fields. The metabolic pathway and genetic regulation of rhamnolipid production in P. aeruginosa are poorly understood. Herein, several proteins directly or indirectly related to rhamnolipid production and their genetic regulations were identified by comparative proteomic. We compared the proteome of P. aeruginosa PA1 after fermentation in two different conditions of carbon and nitrogen sources: condition A allowed rhamnolipid production and condition B prevented it. Protein extracts from cellular pellets were compared using 2D-PAGE stained with colloidal Coomassie followed by MALDI-TOF/TOF mass spectrometry. We identified 21 differentially expressed proteins, including those involved in secretion, quorum sensing, oxidative response and metabolism.     

Effect of carbon and nitrogen sources on the production of penitrem B byPenicillium aurantiogriseum

Effect of different carbon and nitrogen sources on the production of penitrem B was studied.d-Xylose induced maximum penitrem B production, while melibiose, glycerol, citric acid and succinic acid were poor substrates. Potassium nitrate,l-asparagine, sodium nitrate, glycine,dl-aspartic acid andl-tryptophan supported good production of penitrem B. Conversely zirconyl nitrate, barium nitrate, aluminum nitrate, acetanilide, 4-aminobenzoic acid, 4-nitrobenzoic acid and 4-nitroaniline were toxic and did not even permit the growth of the fungus.     

Kinetic studies on surfactant production byPseudomonas aeruginosa 44T1

Summary Biosurfactant accumulation occurred in the exponential and stationary phases. Production started when the nitrogen level was very low. Surfactant was produced with a diauxic pattern. Rhamnolipid concentration increased as nitrogen levels increased. Maximum product yield (Y _p/x) 2.9 was detected when C/N ratio was 6.6 and specific rate of product formation (p _q) was calculated. The examination of these kinetics parameters such as product yield and specific rate of product formation should be taken into account to develop a high efficient production process.     

Iridescent material and the effect of iron on its production byPseudomonas aeruginosa

The nutritional conditions controlling iridescence inPseudomonas aeruginosa were studied using synthetic media solidified with agar. Iron and magnesium were growth-limiting factors in media solidified with dialysed agar. Iridescence only occurred on iron-deficient media and was not suppressed by adding Ca, Cu, Mn and Zn to these media. The ultraviolet absorption spectrum of the iridescent material was almost identical to the spectrum of the pyo I substances which are 2-alkyl-4-quinolinols.The amount of material produced was inversely proportional to the iron content of the medium. Small amounts of material were produced by cells grown at levels of iron optimal for growth. Synthesis of 2-alkyl-4-quinolinol may be a normal metabolic process in the iridescent strains ofPseudomonas aeruginosa. It was enhanced by anthranilic acid and tryptophan; kynurenine and kynurenic acid had no effect. The results can be explained if it is assumed that the activity of iron-requiring enzymes catalizing the breakdown of tryptophan is reduced.Even in the presence of anthranilic acid or tryptophan no material was produced by a non-iridescent strain.     

碳源和氮源对5-酮基-葡萄糖酸生成的影响

氧化葡萄糖杆菌Gluconobacter oxydans可以将葡萄糖氧化成葡萄糖酸,并进一步氧化成2-酮基-葡萄糖酸(2KGA)和5-酮基-葡萄糖酸(5KGA),其中5KGA在催化剂的作用下能够转化为L(+)-酒石酸。为了提高5-酮基-葡萄糖酸产量,以仅生成5KGA的氧化葡萄糖杆菌Gluconobacter oxydans HGI-1为出发菌株,研究不同碳源(蔗糖、乳糖、麦芽糖、淀粉、葡萄糖)和有机氮源(酵母浸粉、鱼粉、玉米浆、黄豆饼粉、棉籽饼粉)对5KGA产量的影响。500 mL摇瓶试验结果表明,当葡萄糖浓度为100 g/L时,5KGA产量最高为98.20 g/L;当有机氮源为酵母浸粉、鱼粉和玉米浆,其添加量的蛋白含量为1.60%时,5KGA产量分别为100.20 g/L、109.10 g/L和99.83 g/L,其中,使用鱼粉的5KGA产量最高,使用玉米浆的5KGA产量比酵母浸粉略低。出于经济考虑,文中选择玉米浆作有机氮源,并在5 L发酵罐中进行分批发酵放大试验,5KGA的产量为93.80 g/L,最大生成速率为3.48 g/(L·h),平均生成速率为1.56 g/(L·h)。结果表明,葡萄糖和玉米浆分别为Gluconobacter oxydans HGI-1规模化生产5KGA的最适碳源和氮源,可利用葡萄糖几乎全部(85.93%)转化为5KGA。     

Effect of carbon and nitrogen sources on xylanase production by Trichoderma harzianum 1073 D3

In order to determine the effect of different carbon and nitrogen sources on xylanase production by Trichoderma harzianum 1073 D3, xylan in the xylanase production medium was replaced with different carbon sources. In order to reduce production time, glucose was added to the production media containing xylan. The effects of sucrose, maltose and lactose were investigated and maximum xylanase activity was observed in the presence of sucrose. Ammonium sulphate was the most appropriate inorganic nitrogen source for xylanase production and urea increased xylanase activity slightly.     

Effect of carbon,nitrogen sources and inducers on ligninolytic enzyme production by Morchella crassipes

The effect of different carbon, nitrogen sources and inducers on growth and ligninolytic activity by Morel mushroom Morchella crassipes was investigated. The maximum growth was observed in mineral salts broth containing glucose as the carbon source and sodium nitrate as the nitrogen source. Among the inducers, chemical inducers inhibited the growth whereas in natural substrates, growth was not affected much. Manganese peroxidase and lignin peroxidase activity were not detected in the medium with different carbon and nitrogen sources, whereas laccase activity varied depending on carbon source (0.7–3.48 U/ml). Among the inducers, natural inducers resulted in an increase in the enzyme activities. Maximum laccase activity was observed in rice straw (12. 6 U/ml) followed by ABTS (11.6 U/ml); Manganese peroxidase activity was maximum in rice straw (14.32 U/l) wheat straw (12.16 U/l) and phenol red (15 U/l) as the inducers, whereas for Lignin peroxidase activity, rice straw (22 U/l), wheat straw (16 U/l) and veratrylalcohol (20 U/l) served as the best inducers.     

Effect of different carbon and nitrogen sources on laccase and peroxidases production by selected Pleurotus species

Pleurotus eryngii, P. ostreatus and P. pulmonarius produced laccase (Lac) both under conditions of submerged fermentation (SF) and solid-state fermentation (SSF) with all of the investigated carbon and nitrogen sources. The highest levels of Lac activity were found in P. eryngii, under SF conditions of dry ground mandarine peels and in P. ostreatus, strain No. 493, under SSF conditions of grapevine sawdust.High levels of peroxidases activities were occurred in P. ostreatus, strain No. 494, and P. pulmonarius, under SSF conditions of grapevine sawdust, whereas in SF, these activities were either very low or absent.After purification of extracellular crude enzyme mixture of investigated species and strain which were grown in the medium with the best carbon sources, the Lac activity measurements revealed two peaks in P. eryngii, three peaks in both P. ostreatus strains and three in P. pulmonarius. Results obtained after purification also showed that the levels of phenol red oxidation in absence of external Mn²⁺ were higher than phenol red oxidation levels in presence of external Mn²⁺.In the medium with the best carbon sources (mandarine peels and grapevine sawdust, respectively), both P. eryngii and P. ostreatus, strain No. 493, showed the highest Lac activity with (NH₄)₂SO₄, as a nitrogen source, with a nitrogen concentration of 20 and 30 mM, respectively.In P. ostreatus, strain No. 494, and P. pulmonarius, the best nitrogen sources for peroxidases production were peptone in a concentration of 0.5% and NH₄NO₃ with a nitrogen concentration of 30 mM, respectively.     

Optimization of lipase production byPseudomonas aeruginosa MB 5001 in batch cultivation

Summary The production ofPseudomonas aeruginosa MB 5001 extracellular lipase was optimized by batch cultivation employing shake flasks and 23-L bioreactors. This enzyme efficiently and selectively bioconverts dimethyl 5-(3-(2-(7-chloroquinolin-2-yl)ethyl)phenyl)4,6-dithianonanedioate (diester) to its (S)-ester acid. Process development studies focused on the identification and optimization of the physicochemical parameters required to achieve maximum lipase production. Of the media evaluated, a peptonized milk-based medium was found to support excellent lipase production and stability. Medium composition and process parameters that supported optimal lipase production were different from those supporting maximum biomass formation. Of the parameters investigated, dissolved oxygen tension had the most significant and unexpected impact on lipase production. Elevated lipase production was achieved whenP. aeruginosa MB 5001 was cultivated in a dissolved oxygen limited environment. Overall, these process development studies resulted in a 100% increase in lipase production when compared to the original shake flask process employing skim milk.     

Effect of different nitrogen and carbon sources on the proteolytic activity

Two-three fold increases in the levels of proteolytic activities in one strain of Bacillus licheniformis (R1-8) were obtained when changes in the nature of the nitrogen source (food and fodder yeast instead of soybean meal) and in the amount of invert sugars in the culture medium were performed.     

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.     

Influence of carbon and nitrogen sources on glucoamylase production byAspergillus in batch process

Summary Glucoamylase production kinetics was greatly affected by medium composition. While maltose and cassava flour induced glucoamylase synthesis, fructose clearly repressed it, reaching a maximum enzyne activity value (A_m) of only 6% of those obtained with the former carbon sources. Among the nitrogen sources the best result was obtained with urea, reaching A_m values of about 40% higher than those obtained with ammonium sulphate.     

碳素和氮素对Coriolus versicolor胞外酶分泌的影响

采用单因子相互比较法研究了不同碳素和氮素对彩绒革盖菌胞外漆酶,愈创木酚氧化酶,多酚氧化酶,锰过氧化物酶等木素降解酶分泌的影响,结果淀粉作碳源,干酪素作氮源有利于漆酶的分泌,麦芽粉作碳源,酵母膏作氮源有利于愈创木酚氧化酶和多酚氧化酶的分泌,淀粉作碳源,玉米粉作氮源有利于锰过氧化物酶的分泌。     

Effect of carbon and nitrogen sources on the production of a highly enantioselective epoxide hydrolase from Aspergillus niger

The highly enantioselective epoxide hydrolase from Aspergillus niger is well utilized as biocatalysts for the preparation of enantiopure chiral epoxides and diols. Both growth of the fungus and EH activity production were found greatly affected by changing the carbon or the nitrogen source with fructose and corn steep liquor being the best. Their concentrations were optimized (10 g.l–1 of fructose and 15 g.l–1 of corn steep) which resulted in an increase of both the biomass produced (31%) and the epoxide hydrolase specific activity (38%). The results obtained suggested a complex regulation of the EH production. On the whole, a two times increase of the total EH activity was obtained. © Rapid Science Ltd. 1998     

Peroxidase production by carbon and nitrogen sources fed-batch culture of Arthromyces ramosus

Summary Carbon and nitrogen sources were investigated for improving peroxidase production by Arthromyces ramosus, a hyperproducer of peroxidase. Glucose as carbon source and a mixture of yeast extract and polypeptone at the ratio of 3 to 5 as nitrogen source in a production medium were shown to give the highest peroxidase activity. During the culture amino acids such as alanine, arginine, methionine, leucine, tyrosine and tryptophan were depleted. Therefore, glucose supplemented nitrogen source fed-batch culture was carried out and a peroxidase activity of 73 U/ml was obtained. This activity was 1.7 times higher than that of glucose fed-batch culture. This indicates that an adequate nitrogen source supply during the culture is effective for improving the peroxidase production by A. ramosus.     

Degradation of different hydrocarbons and production of biosurfactant byPseudomonas aeruginosa isolated from coastal waters

Summary A bacterium isolated from an oil spillage sample and identified asPseudomonas aeruginosa degraded hexadecane and heptadecane by 47% and 58% with 9% and 12% of total carbon from the respective substrates being liberated as CO₂. With octadecane and nonadecane as substrates, 73% and 60% were biodegraded while 27% and 25% of total carbon was evolved as CO², respectively. Production of biosurfactant by this bacterium was studied using hexadecane 5% (v/v) as substrate. The surface tension of spent culture medium, as well as the supernatant, was 30 mN/m compared to 71 mN/m for water. When the supernatant was mixed with hexadecane (15, v/v) a stable emulsion was formed which deteriorated only by 10% after one month.

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Dégradation de différents hydrocarbures et production de biosurfactants parPseudomonas aeruginosa isolé d'eaux côtières

Résumé Une bactérie, isolée d'un échantillon d'hydrocarbures épandus, et identifiée commePseudomonas aeruginosa, dégrade l'hexaet l'heptadécane à raison respective de 47 et de 58% du carbone total avec 9 et 12% des substrats respectifs libérés sous la forme de CO₂. Avec l'octa- et le nonadécane comme substrats, la biodégradation atteint respectivement 73 et 60% avec 27 et 25% du carbone total transformé en CO₂. On a étudié la production de biosurfactant par cette bactérie en utilisant l'hexadécane à 5% (v/v) comme substrat. La tension superficielle de la liqueur mixte, comme celle de son surnageant atteint 30 mN/m par comparaison à 71 mN/m pour l'eau. Lorsque le surnageant est mélangé à l'hexadécane (15, v/v), on forme une émulsion stable qui ne se détériore que de 10% au bout d'un mois.

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This work was carried out at the Biotechnology Laboratories of the Nuclear Institute for Agriculture & Biology (NIAB), Faisalabad.