Citric acid production by selected mutants of Aspergillus niger from cane molasses (original) (raw)
2004, Bioresource Technology
The present investigation deals with citric acid production by some selected mutant strains of Aspergillus niger from cane molasses in 250 ml Erlenmeyer flasks. For this purpose, a conidial suspension of A. niger GCB-75, which produced 31.1 g/l citric acid from 15% (w/v) molasses sugar, was subjected to UV-induced mutagenesis. Among the 3 variants, GCM-45 was found to be a better producer of citric acid (50.0 ± 2a) and it was further improved by chemical mutagenesis using N-methyl, N-nitro-N-nitrosoguanidine (MNNG). Out of 3,2-deoxy-D D -glucose resistant variants, GCMC-7 was selected as the best mutant, which produced 96.1 ± 1.5 g/l citric acid 168 h after fermentation of potassium ferrocyanide and H 2 SO 4 pre-treated blackstrap molasses in Vogel's medium. On the basis of kinetic parameters such as volumetric substrate uptake rate (Q s ), and specific substrate uptake rate (q s ), the volumetric productivity, theoretical yield and specific product formation rate, it was observed that the mutants were faster growing organisms and produced more citric acid. The mutant GCMC-7 has greater commercial potential than the parental strain with regard to citrate synthase activity. The addition of 2.0 · 10 À5 M MgSO 4 AE 5H 2 O into the fermentation medium reduced the Fe 2þ ion concentration by counter-acting its deleterious effect on mycelial growth. The magnesium ions also induced a loose-pelleted form of growth (0.6 mm, diameter), reduced the biomass concentration (12.5 g/l) and increased the volumetric productivity of citric acid monohydrate (113.6 ± 5 g/l).
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Production of citric acid by Aspergillus niger using cane molasses in a stirred fermentor
The present investigation deals with the kinetics of submerged citric acid fermentation by Aspergillus niger using blackstrap molasses as the basal fermentation media. A laboratory scale stirred fermentor of 15-L capacity having working volume of 9-L was used for cultivation process and nutritional analysis. Among the 10 stock cultures of Aspergillus niger, the strain GCBT7 was found to enhance citric acid production. This strain was subjected to parametric studies. Major effects were caused due to oxygen tension (1.0 l/l/min), pH value (6.0) and incubation temperature (30ºC). All fermentations were carried out following the growth on 150 g/l raw molasses sugars for 144 hours. Ferrocyanide (200 ppm) was used to control the trace metals present in the molasses medium. Ammonium nitrate (0.2%) was added as nitrogen source. Maximum citric acid production (99.56 ± 3.5a g/l) was achieved by Aspergillus *Corresponding author niger GCBT7. The dry cell mass and sugar consumption were 18.5 and 96.55 g/l, respectively. The mycelia were intermediate round pellets in their morphology. The specific productivity of GCBT7 (qp = 0.074 ± 0.02a g/g cells/h) was several folds higher than other strains. The specific production rate and growth coefficient revealed the hyperproducibility of citric acid using mutant GCBT7.
Production of citric acid by Aspergillus niger
The present investigation deals with the kinetics of submerged citric acid fermentation by Aspergillus niger using blackstrap molasses as the basal fermentation media. A laboratory scale stirred fermentor of 15-L capacity having working volume of 9-L was used for cultivation process and nutritional analysis. Among the 10 stock cultures of Aspergillus niger, the strain GCBT7 was found to enhance citric acid production. This strain was subjected to parametric studies. Major effects were caused due to oxygen tension (1.0 l/l/min), pH value (6.0) and incubation temperature (30ºC). All fermentations were carried out following the growth on 150 g/l raw molasses sugars for 144 hours. Ferrocyanide (200 ppm) was used to control the trace metals present in the molasses medium. Ammonium nitrate (0.2%) was added as nitrogen source. Maximum citric acid production (99.56 ± 3.5a g/l) was achieved by Aspergillus *Corresponding author niger GCBT7. The dry cell mass and sugar consumption were 18.5 and 96.55 g/l, respectively. The mycelia were intermediate round pellets in their morphology. The specific productivity of GCBT7 (qp = 0.074 ± 0.02a g/g cells/h) was several folds higher than other strains. The specific production rate and growth coefficient revealed the hyperproducibility of citric acid using mutant GCBT7.
Some factors affecting citric acid production from sugar cane molasses by Aspergillus niger
The production of citric acid from cane molasses by Aspergillus niger in submerged culture was investigated. Different factors were affected on the citric acid production and the results revealed that: The highest value of citric acid concentration 29.84 g/l was obtained with 1.5 g/l K4Fe(CN)6. Maximum productivity of citric acid was obtained with the treatment of cane molasses with 10 g/l ammonium oxalate. At 0.20 g/l MgSO4.7H2O, citric acid reached its maximum being 33.2 g/L. 5x106 spores/100 ml was the best inoculum volume and citric acid concentration was 32.88. Certain metal ions are known to be inhibitory and some of it have stimulatory effect of citric acid production. Zn++ was have an inhibitory effect but Ca++ was have the stimulatory effect and citric acid production was 18.44, 32.51 g/l respectively. In the absence of ethanol, citric acid reached its maximum being 33.61 g/l. The air supply resulted in improved citric acid concentration being 51.1 g/l after 8 days. Citric ...
Two starchy substrates like pumpkin and cane molasses were selected for citric acid fermentation by using gamma ray induced mutant strains of 14/20 and 79/20 of A. niger under surface culture condition. Citric acid production was also different with various fermentation media by A. niger 14/20 and 79/20 strains. It was found to increase with the increase of fermentation period and maximum citric acid was found on day 13. In the presence of Prescott salt citric acid production was found lower than the absence of Prescott salt. Without Prescott salt highest values of citric acid production was found in mixed fermentation medium which were about 14.86 mg/ml and 14.44 mg/ml for A. niger 14/20 and 79/20 strains respectively, lowest production of citric acid was found in molasses medium for A. niger 14/20 and 79/20 strains were 7.72 and 7.57 mg/ml respectively. Whereas in the presence of Prescott salt, lowest production of citric acid in Pumpkin medium was found 2.86 mg/ml for A. niger 14/20 and 2.7 mg/ml for A. niger 79/20. Highest amount of citric acid was produced in molasses medium 4.88 mg/ml for A. niger 14/20 on day 13 with the presence of Prescott salt whereas 4.75 mg/ml for A. niger 79/20 strains respectively. Mixed substrate prepared with molasses and pumpkin media was proved to be the best and potential for citric acid production.
Under surface culture condition, a number of cheap indigenous raw materials like cane molasses and jackfruits were selected for citric acid fermentation and gamma ray induced mutant strains of 14/20 and 79/20 of Aspergillus niger were used. The rate of citric acid production was also influenced by biomass production and residual sugar used. In both cases on the day 13 without presence of Prescott salt for the mutant strain of Aspergillus niger 14/20 the citric acid production was highest. The biomass production was found different in various fermentation medium. It was found to increase with the increase of fermentation period and maximum biomass was found on day 13. It is also found that biomass production was higher in mutant strain of A. niger 14/20 than 79/20. In addition to this, wet-weight biomass was higher than dry weight biomass. Without presence of Prescott salt, wet weight of mycelial body of the fungus Aspergillus niger 14/20 was found highest on day 13 in mixed substrates which was 160.15. Mixed substrate prepared with molasses and jackfruit media was proved to be the best and potential for biomass production. Sugar utilization rate was also different in various media during citric acid production by A. niger 14/20 and 79/20. Prescott salt was also found to have remarkable effect on sugar utilization for citric acid production except on days 0, 3 and 5. In presence of Prescott salt, sugar utilization was lower than without presence of Prescott salt in the molasses, jackfruit and mixed fermentation media during production of citric acid. With the increase of fermentation period, sugar concentration in the medium was reduced and maximum reduction was found on day 13. Without presence of Prescott salt and in mixed fermentation medium the highest production of citric acid was found by further mutated Aspergillus niger 14/20 which was about 16.16mg/ml.
Enhanced Production of Citric Acid by Aspergillus niger M-101 Using Lower Alcohols
Turk Biyokimya Dergisi Turkish Journal of Biochemistry, 2010
Objective: Citric acid is mainly produced by submerged fermentation of Aspergillus niger. The process yield depends on the composition of the medium, as well as on the microorganism strain. Materials and Methods: In the present study citric acid production by Aspergillus niger M-101 using lower alcohols such as methanol and ethanol at concentration of 0.5 to 2.0 % (v/v) was optimized in shake flask culture using beet molasses as fermentation medium. Results: Methanol (1.5 %) and ethanol (1 %) was found optimal for maximum citric acid production (49.33±4.23 g/l) and (40.85±0.48 g/l) respectively. The effect of addition of ethanol and methanol to the fermentation medium at different time intervals on citric acid production demonstrate that maximum citric (44.62±2.12 g/l) and (55.13±1.53 g/l) was produced after 30 h and 45 h of incubation period. The yield for methanol and ethanol was 1.54 and 2.33 higher than the control experiment. Conclusion: From the present study it is concluded that both methanol and ethanol under optimized conditions increases the permeability of cell membrane of Aspergillus niger M-101 that result in accumulation of citric acid in fermentation medium. The kinetic assessments demonstrate that there was a significant enhancement (p ≤ 0.05) in citric acid production over the control fermentation medium. The best results for the production of citric acid were observed after 192 h of fermentation period.
Citric Acid Production by Aspergillus niger Using Molasses and Pumpkin as Substrates
Two starchy substrates like pumpkin and cane molasses were selected for citric acid fermentation by using gamma ray induced mutant strains of 14/20 and 79/20 of A. niger under surface culture condition. Citric acid production was also different with various fermentation media by A. niger 14/20 and 79/20 strains. It was found to increase with the increase of fermentation period and maximum citric acid was found on day 13. In the presence of Prescott salt citric acid production was found lower than the absence of Prescott salt. Without Prescott salt highest values of citric acid production was found in mixed fermentation medium which were about 14.86 mg/ml and 14.44 mg/ml for A. niger 14/20 and 79/20 strains respectively, lowest production of citric acid was found in molasses medium for A. niger 14/20 and 79/20 strains were 7.72 and 7.57 mg/ml respectively. Whereas in the presence of Prescott salt, lowest production of citric acid in Pumpkin medium was found 2.86 mg/ml for A. niger 14/20 and 2.7 mg/ml for A. niger 79/20. Highest amount of citric acid was produced in molasses medium 4.88 mg/ml for A. niger 14/20 on day 13 with the presence of Prescott salt whereas 4.75 mg/ml for A. niger 79/20 strains respectively. Mixed substrate prepared with molasses and pumpkin media was proved to be the best and potential for citric acid production.
Folia Microbiologica, 1992
Two starchy substrates like pumpkin and cane molasses were selected for citric acid fermentation by using gamma ray induced mutant strains of 14/20 and 79/20 of A. niger under surface culture condition. Citric acid production was also different with various fermentation media by A. niger 14/20 and 79/20 strains. It was found to increase with the increase of fermentation period and maximum citric acid was found on day 13. In the presence of Prescott salt citric acid production was found lower than the absence of Prescott salt. Without Prescott salt highest values of citric acid production was found in mixed fermentation medium which were about 14.86 mg/ml and 14.44 mg/ml for A. niger 14/20 and 79/20 strains respectively, lowest production of citric acid was found in molasses medium for A. niger 14/20 and 79/20 strains were 7.72 and 7.57 mg/ml respectively. Whereas in the presence of Prescott salt, lowest production of citric acid in Pumpkin medium was found 2.86 mg/ml for A. niger 14/20 and 2.7 mg/ml for A. niger 79/20. Highest amount of citric acid was produced in molasses medium 4.88 mg/ml for A. niger 14/20 on day 13 with the presence of Prescott salt whereas 4.75 mg/ml for A. niger 79/20 strains respectively. Mixed substrate prepared with molasses and pumpkin media was proved to be the best and potential for citric acid production.
Production and Optimization of Citric Acid by Aspergillus Niger Using Molasses and Corncob
International Journal of Pharmacy and Pharmaceutical Sciences, 2015
Objective: The present study made an attempt to produce commercially valuable citric acid by the fungal strain Aspergillus niger from molasses and corncob using submerged fermentation, as the best alternative to the sugar substrate. Methods: Three types of production media were prepared including control (sucrose) by following standard fermentation conditions. The acid production was indicated by the reduction of pH levels. The citric acid content and residual sugars of the final hydrolysate were estimated by the Marrier and Boulet method and Anthrone Sulphuric acid method respectively. Results: The control production medium gave yield of 4.6 milligrams per milliter (mg/ml) at pH 3.0 on 10 th Conclusion: Molasses and corncob when replaced with sucrose in the fermentation medium produced significant amount of citric acid. The results imply the effective use of molasses and corncob as an alternative substrate for the production of commercially valuable, citric acid with a cost effective approach. day. The medium containing molasses and other compositions gave the yield of 10.4 mg/ml, whereas corncob medium and other compositions gave the yield of 5.3 mg/ml at pH 2.5. The medium containing molasses and corncob separately with 5 percent (%) sucrose gave the highest yield of 12.6 mg/ml and 6.7 mg/ml at pH 3.0 respectively. Different factors affecting citric acid production by fermentation were also studied. Sucrose was found superior for maximum citric production at optimum incubation temperature at 30 degree Celsius (⁰C). The nitrogen supplements, ammonium sulphate and ammonium chloride at a concentration of 0.25 % and 0.5% respectively gave the highest yield, whereas the methanol concentration of 2% was found optimum for obtaining maximum yield of citric acid.
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