Citric Acid Production by Wild and UV – Treated Strains of Aspergillus niger on Two Different Mineral Salt Media (original) (raw)
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Biosynthesis of Citric Acid by Locally Isolated Aspergillus niger Using Sucrose Salt Media
Journal of Biological Sciences, 2001
Sixteen different cultures of Aspergillus niger were isolated from different soil samples. These isolates of Aspergillus niger were evaluated for citric acid fermentation in shake flask. Sucrose salt media was used and the volume of fermentation medium was kept at 25 ml. The cultural conditions such as pH (3.5), temperature (30EC), incubation period (8 days) and sugar concentration (15%), were optimised.
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.
Factors controlling citric acid production by some of Aspergillus niger strains
Different strains of A. niger were used to examine their ability to produce citric acid and the results revealed that most of the nine tested strains were able to produce citric acid. A. niger CA2 was the highest producer strain during the fermentation on medium No. 2, while highest biomass weight was obtained during the growth of A. niger CA2 on medium No.1. But, highest value of consumption of sugars was found during the growth of A. niger NRRL 2270 on medium No.5. Highest value of conversion coefficient and the citric acid yield were obtained during the growth of A. niger CA2 on medium No. 2. Maximum production of citric acid was obtained after 8 days of fermentation and pH 5.5. At the same time, highest value of biomass, conversion coefficient and total sugars consumed were obtained at these conditions. At 15% sugars concentration, citric acid reached its maximum being 29.3 g/L. Maximum production (32.03 g/L) of citric acid was obtained with 2.0 g/L ammonium phosphate, also, give highest amount of biomass and citric acid yield. Highest value of citric acid concentration (32.88 g/L) and citric acid yield (21.92%) were obtained with 0.3 ml/L of phosphoric acid which was found as the best phosphorus source.
Citric Acid Production Potential of Aspergillus niger Using Chrysophyllum albidum Peel
Advances in Bioscience and Biotechnology
The production of citric acid using Chrysophyllum albidum an indigenous under-utilized fruit waste peel and genetically characterized strains of Aspergillus niger was carried out. The Chrysophyllum albidum peel was dried, sieved to remove dirt, dry milled and the powder used as substrate for citric acid production. Thirteen fungal isolates were obtained from soil samples and decayed agricultural waste by spread plate technique and screened for citric acid producing capabilities on Czapek dox agar. Citric acid producing capability of the isolates revealed a wide yellow zone around the inoculated colonies. Two (F1 and F3) out of the thirteen isolates exhibited positive reactions and were identified based on their cultural, morphological and molecular characteristics. The fungal species were identified using PCR as Aspergillus niger DTO: 133-E8 and Aspergillus niger DTO: 131-H5. Their cultural/growth optimal conditions were determined through Solid State Fermentation of the substrate using two species of the test organism. The effects of fermentation period examined revealed, Aspergillus niger DTO: 133-E8 which produced the highest amount of citric acid 15.7 ± 0.08 g/l, lower reducing sugar and final pH of 2.1 and 121.5 ± 0.31 g/l respectively after 192 h of growth at 30˚C. Aspergillus niger DTO: 131-H5 showed highest amount of citric acid 10.2 ± 0.22 g/l, lower reducing sugar and final pH of 2.4 and 128.5 ± 0.15 g/l respectively after 192 h of growth at 30˚C. Maximum concentration of citric acid ranging between 16.3 ± 0.30 g/l and 12.6 ± 0.11 g/l with reducing sugar 125.4 ± 0.11 g/l and 127.2 ± 0.03 g/l was achieved at an initial pH of 5.5. Methanol was used to stimulate citric acid production (0%-3% (v/v)) and was found to be effective at 2% (v/v) level with 21.2 ± 0.20 g/l of citric acid produced with residual sucrose concentration of 129.5 ± 0.44 g/l. The effect of trace element on citric acid production showed that Cu 2+ and Fe 2+ stimulated citric acid production; while other ions reduced citric acid production. There was a statistically significant difference (P > 0.05) between the citric acid produced with the various parameters investigated in this research.
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.
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.
Citric Acid Production Potential of Aspergillus niger Using Chrysophyllum albidum Peel
Advances in Bioscience and Biotechnology, 2018
The production of citric acid using Chrysophyllum albidum an indigenous under-utilized fruit waste peel and genetically characterized strains of Aspergillus niger was carried out. The Chrysophyllum albidum peel was dried, sieved to remove dirt, dry milled and the powder used as substrate for citric acid production. Thirteen fungal isolates were obtained from soil samples and decayed agricultural waste by spread plate technique and screened for citric acid producing capabilities on Czapek dox agar. Citric acid producing capability of the isolates revealed a wide yellow zone around the inoculated colonies. Two (F1 and F3) out of the thirteen isolates exhibited positive reactions and were identified based on their cultural, morphological and molecular characteristics. The fungal species were identified using PCR as Aspergillus niger DTO: 133-E8 and Aspergillus niger DTO: 131-H5. Their cultural/growth optimal conditions were determined through Solid State Fermentation of the substrate using two species of the test organism. The effects of fermentation period examined revealed, Aspergillus niger DTO: 133-E8 which produced the highest amount of citric acid 15.7 ± 0.08 g/l, lower reducing sugar and final pH of 2.1 and 121.5 ± 0.31 g/l respectively after 192 h of growth at 30˚C. Aspergillus niger DTO: 131-H5 showed highest amount of citric acid 10.2 ± 0.22 g/l, lower reducing sugar and final pH of 2.4 and 128.5 ± 0.15 g/l respectively after 192 h of growth at 30˚C. Maximum concentration of citric acid ranging between 16.3 ± 0.30 g/l and 12.6 ± 0.11 g/l with reducing sugar 125.4 ± 0.11 g/l and 127.2 ± 0.03 g/l was achieved at an initial pH of 5.5. Methanol was used to stimulate citric acid production (0%-3% (v/v)) and was found to be effective at 2% (v/v) level with 21.2 ± 0.20 g/l of citric acid produced with residual sucrose concentration of 129.5 ± 0.44 g/l. The effect of trace element on citric acid production showed that Cu 2+ and Fe 2+ stimulated citric acid production; while other ions reduced citric acid production. There was a statistically significant difference (P > 0.05) between the citric acid produced with the various parameters investigated in this research.