Substrate For Citric Acid Production Research Articles

Assessing Waste Sunflower Oil as a Substrate for Citric Acid Production: The Inhibitory Effect of Triton X-100

In this study, waste sunflower oils were evaluated as substrates for citric acid (CA) production by Yarrowia lipolytica IFP29 (ATCC 20460). This strain was selected based on its capacity to produce organic acids in a selective medium. Attempts were made to optimize the process using the Taguchi statistical method in terms of the oil polarity, oil concentration, fermentation time, and Triton X-100 concentration. The results indicated that Y. lipolytica IFP29 utilized waste sunflower oil as a substrate and produced a maximum CA of 32.17 ± 1.44 g/L. Additionally, Triton X-100 inhibited the production of CA. For this reason, this process could not be optimized. These results were obtained by periodically adjusting the pH with NaOH during the fermentation period. On the other hand, a new experimental design was created without Triton X-100. As a buffering agent, 2-morpholinoethanesulfonic acid monohydrate (MES) was used to prevent a drop in pH; the maximum concentration of CA was found to be 20.31 ± 2.76. The optimum conditions were as follows: 90 g/L of waste sunflower oil with a polarity of 16 and 12 days of fermentation. According to the analysis of variance results, the effects of factors other than polarity on CA production were found to be significant (p < 0.05).

The Effect of Copper (II) ion on the Production of Citric Acid by Aspergillus niger using Corncobs

Citric acid production using agro-waste as cheap carbon source helps in waste management and reduction in cost of production. The study was aimed at optimizing citric acid production from corncobs as substrate was amended with copper ions. Corncobs were collected, air dried, milled and pretreated with acid hydrolysis. The pretreated corncob media were inoculated with 106 spores/ml of Aspergillus niger and fermented for 10 d at 28 \(\pm\) 2 °C. Effect of corncob concentrations of 5 – 25 % w/v on citric acid production was examined. The concentration with highest yield of citric acid was optimized using copper ions concentration of 0 – 0.4 g/l. All through the fermentation processes samples analyzed were citric acid produced, fungal biomass, and changes in pH. The supplemented corncob medium had the highest citric acid production and fungal biomass after 8 d of fermentation. Studies on corncob concentrations showed that 25 %w/v of corncobs had the highest citric acid production and fungal biomass. The highest citric acid production and fungal biomass of 2.94\(\pm\) 0.05 and 3.11\(\pm\) 0.04 g/l respectively were observed in the medium amended with 0.3 g/l of copper ions. Statistically, the values were significantly different from other concentrations of copper ions (p< 0.05). Corncob was observed to be a good substrate for citric acid production by A. niger and amendment of substrate with copper ions at lower concentration can help to optimize the production of citric acid.

Utilization of Pap processing waste in submerged culture of Aspergillus niger enriched with poultry dropping extract for citric acid production

Determining the potential of pap processing waste for citric acid production was investigated using Aspergillus niger isolated from pap waste. The cost of substrate for citric acid production represents a significant percentage of the total production cost. The aim of this work was therefore, to utilize pap processing waste in submerged culture enriched with poultry dropping extract for citric acid production. The effect of initial pH, inoculums size, poultry dropping extract, pap processing waste concentration and alcohol addition were investigated on citric acid production from pap processing waste. The results show that the initial pH, inoculums size, poultry dropping extract, pap processing waste and methanol had significant effect on citric acid production from pap processing waste (p< 0.05). Citric acid concentration increased as the pH increased. A pH value of 6.0 was the optimum for maximum citric acid concentration of 6.5 ± 0.116 g/l after 96 hours of fermentation. Citric acid concentration also increased as the percentage inoculums increased. A 10 % inoculums size was the optimum with the maximum concentration of 8.0 ± 0.231 g/l citric acid. There is also an increase in citric acid concentration as the percentage poultry dropping extract concentrations increased from 5 % to 15 %. A 15 % poultry dropping extract concentrations was the optimum with the maximum concentration of 11.0 ± 0.251 g/l citric acid. As the concentration of the pap processing waste increased up to 20 % the citric acid concentration of 16.0 ± 0.413 g/l was produced after 96 hours of fermentation. A 3 % methanol addition was the optimum with the maximum citric acid concentration of 26.0 ± 0.351 g/l after 96 hours of fermentation. This research work has established the potential of pap processing waste on citric acid production if well harnessed.

Exploring cocoa pod husks as a potential substrate for citric acid production by solid-state fermentation using Aspergillus niger mutant strain

The aim of this work was to use the cocoa pod husks (CPHs) as a new substrate/support for citric acid (CA) production by Aspergillus niger strains in solid-state fermentation (SSF). Actually, CPH does not have a proper final destination, and its characteristics are suitable to be used as sole substrate in SSF for CA production. Partial physical-chemical characterization of CPHs showed interesting composition and potential for fungal growth. The mutant A. niger B6 – CCT 7717 was previously screened due to its great capacity of CA production. The peak of CA production 978.52 g kg−1 of dry CPHs was reached at 72 h with a yield of 88.70 % (dry CPHs) and a productivity of 13.59 g kg h−1, surpassing the highest reported rates of CA production. Great perspectives are viewed for this process.

EVALUATION OF POMEGRANATE PEEL AS A SUBSTRATE FOR CITRIC ACID PRODUCTION BY ASPERGILLUS NIGER

Objective: The present study aimed to evaluate dried pomegranate peels as a substrate for citric acid production by Aspergillus niger.
 Methods: The morphological study of Aspergillus niger was carried out by wet mount with lactophenol cotton blue and slide culture method. A preliminary qualitative screening of citric acid-producing ability of this fungal strain was also performed by using the Czapek-Dox agar medium containing Bromocresol green. Dried and finely powdered Pomegranate peel was used as a principal substrate for the production of citric acid by submerged fermentation. Classical method of citric acid recovery involved a precipitation technique using calcium hydroxide followed by filtration and subsequent treatment with sulphuric acid. The citric acid produced was also chemically detected and titrimetrically estimated by 0.1 N NaOH.
 Results: The present experiment demonstrated that pomegranate peels may serve as an inexpensive medium for the production of citric acid with a yield of 19.39 g/l by using Aspergillus niger.
 Conclusion: This study provided an alternative basis to recycle the fruit peel waste of pomegranate in order to achieve industrially feasible and environmentally sustainable bio-production of pharmaceutically significant citric acid.

Pomegranate peel waste: a new substrate for citric acid production by Aspergillus niger in solid-state fermentation under non-aseptic conditions.

Citric acid production from dried and non-dried pomegranate peel wastes by the fungus Aspergillus niger B60 in solid-state fermentation (SSF) under non-aseptic conditions was investigated. The maximum amount of citric acid (278.5g/kg dry peel) was achieved using dried (at 45°C for 48h) pulverized pomegranate peels with moisture content 75% and initial pH8.0, after 8days of fermentation at 25°C. Under the same fermentation conditions, a higher amount of citric acid (306.8g/kg dry peel) was observed during SSF of non-dried peels as a substrate. The addition of methanol as an inducer at a concentration of 3% (w/w) into the dried and non-dried pomegranate peel wastes increased the amount of citric acid to 300.7 and 351.5g/kg dry peel, respectively. The non-dried pomegranate peel waste in SSF under non-aseptic conditions is a cheap and useful substrate for the commercial production of citric acid with low energy cost. The utilization of inexpensive agro-industrial wastes through SSF can contribute to achieve industrially feasible and environmentally sustainable bio-production of citric acid.

Citric Acid Production Potential of <i>Aspergillus niger</i> Using <i>Chrysophyllum albidum</i> Peel

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 Cu2+ and Fe2+ 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. From the study, it has been found that Chrysophlum albidum is suitable for the cultivation of Aspergillus niger and has great potential for citric acid production and could be exploited to promote certain industrial applications of underutilized fruits in Nigeria. This can be an application of waste to wealth as well as a way of minimizing agro-based environmental pollution for a cleaner environment.

Citric Acid Production by Aspergillus niger Cultivated on Parkia biglobosa Fruit Pulp.

The study was conducted to investigate the potential of Parkia biglobosa fruit pulp as substrate for citric acid production by Aspergillus niger. Reducing sugar was estimated by 3,5-dinitrosalicylic acid and citric acid was estimated spectrophotometrically using pyridine-acetic anhydride methods. The studies revealed that production parameters (pH, inoculum size, substrate concentration, incubation temperature, and fermentation period) had profound effect on the amount of citric acid produced. The maximum yield was obtained at the pH of 2 with citric acid of 1.15 g/L and reducing sugar content of 0.541 mMol−1, 3% vegetative inoculum size with citric acid yield of 0.53 g/L and reducing sugar content of 8.87 mMol−1, 2% of the substrate concentration with citric acid yield of 0.83 g/L and reducing sugar content of 9.36 mMol−1, incubation temperature of 55°C with citric acid yield of 0.62 g/L and reducing sugar content of 8.37 mMol−1, and fermentation period of 5 days with citric acid yield of 0.61 g/L and reducing sugar content of 3.70 mMol−1. The results of this study are encouraging and suggest that Parkia biglobosa pulp can be harnessed at low concentration for large scale citric acid production.

Effects of Different Oil Sources and Residues on Biomass and Metabolite Production by Yarrowia lipolytica YB 423‐12

AbstractYarrowia lipolytica is known to have the ability to assimilate hydrophobic substrates like triglycerides, fats, and oils, and to produce single‐cell oils, lipases, and organic acids. The aim of the present study was to investigate the effects of different oil sources (borage, canola, sesame, Echium, and trout oils) and oil industry residues (olive pomace oil, hazelnut oil press cake, and sunflower seed oil cake) on the growth, lipid accumulation, and lipase and citric acid production by Y. lipolytica YB 423‐12. The maximum biomass and lipid accumulation were observed with linseed oil. Among the tested oil sources and oil industry residues, hazelnut oil press cake was the best medium for lipase production. The Y. lipolytica YB 423‐12 strain produced 12.32 ± 1.54 U/mL (lipase activity) of lipase on hazelnut oil press cake medium supplemented with glucose. The best substrate for citric acid production was found to be borage oil, with an output of 5.34 ± 0.94 g/L. The biotechnological production of valuable metabolites such as single‐cell oil, lipase, and citric acid could be achieved by using these wastes and low‐cost substrates with this strain. Furthermore, the cost of the bio‐process could also be significantly reduced by the utilization of various low‐cost raw materials, residues, wastes, and renewable resources as substrates for this yeast.

Optimization of Sweet Potato Starch Hydrolyzate Production and Its Potential Utilization as Substrate for Citric Acid Production

Aims: The aims of this work was optimization of two -step enzymatic hydrolysis of sweet potato starch using statistical approach and subsequent utilization of the hydrolyzate obtained for citric acid production. Methodology: Box Behnken design was used in this s tudy to generate a total of 17 individual experiments for each step of the hydrolysis (liquefaction and saccharification steps). These were designed to study the effect of temperature, time and pH on the sweet potato starch hydrolyzate (SPSH) concentration . The optimization was carried out using response surface methodology (RSM). The SPSH obtained was used to culture Aspergillus nigerfor citric acid production. Results:A statistically significant quadratic regression model (P<

Utilization of different agro-industrial wastes for sustainable bioproduction of citric acid by Aspergillus niger

In view of ever growing demand of citric acid, there is an urgent need to look for inexpensive and novel substrates for feasible production of citric acid. In this context, the present study was carried out to evaluate the potential of different agro-industrial wastes for hyper production of citric acid through solid-state and submerged fermentation by Aspergillus niger NRRL 567 and NRRL 2001. It was found that among all the solid substrates utilized, apple pomace with 66.0 ± 1.9 g/kg of dry substrate proved to be an excellent substrate for citric acid production by A. niger NRRL 567 at 72 h of incubation. A. niger NRRL 2001 resulted in slightly lower citric acid concentration of 61.0 ± 1.9 g/kg of dry substrate at the same incubation time. APS-1 (apple pomace ultrafiltration sludge-1) gave highest citric acid production rate of 9.0 ± 0.3 g/l and 8.9 ± 0.3 g/l of substrate by A. niger NRRL 567 and NRRL 2001 by submerged fermentation, respectively. Further study with apple pomace and apple pomace ultrafiltration sludge-1 by A. niger NRRL 567 was carried out. Addition of 3% (v/w) ethanol and 4% (v/w) methanol to apple pomace gave significantly higher citric acid values of 127.9 ± 4.3 g/kg and 115.8 ± 3.8 g/kg of dry substrate by A. niger NRRL 567 by solid-state fermentation. Higher citric acid values of 18.2 ± 0.4 g/l and 13.9 ± 0.4 g/l of apple pomace ultrafiltration sludge-1 were attained after addition of 3% (v/v) ethanol and 4% (v/v) methanol, respectively by A. niger NRRL 567. Apple pomace solid waste and apple pomace ultrafiltration sludge-1 thus proved to be an excellent source for citric acid production, of the different substrates chosen.

Production of citric acid from ram horn hydrolysate by Aspergillus niger

Ram horn hydrolysate (RHH) was used as a substrate for the microbial production of citric acid using Aspergillus niger NRRL 330 in a submerged culture. Ram horns were hydrolyzed by treating with acid (6N–H 2SO 4) and neutralizing the solution. The amounts of protein, nitrogen, ash, some minerals, total sugars, total lipids and amino acids of the RHH were determined. The effect of different concentrations (1–10% v/v) of RHH on the production of biomass was investigated and a concentration of 8% RHH was found to be optimal. The content of citric acid in the culture broth containing 8% RHH (78 g/l) for 6 d was 26% higher than that of the control culture broth (62 g/l). From this result, RHH was demonstrated to be a suitable substrate for citric acid production. RHH may be a valuable supplement in biotechnology.

Yam bean starch: a novel substrate for citric acid production by the protease-negative mutant strain of Aspergillus niger

Selection of protease-negative mutant strains of Aspergillus niger in semi-solid culture was carried out in order to enhance citric acid production from yam bean. The protease-negative mutants were obtained by UV-irradiation of the parental strain Yang no. 2. Using a halo-selection medium, a number of mutants with decreased extracellular protease activity were selected. Citric acid productivity by the selected mutant strains was tested on a modified starch–methyl red agar plate. The best mutant strain YW-112 was obtained and produced 106 g/l of citric acid, whereas the parental strain Yang no. 2 produced 58 g/l, from 140 g/l of soluble starch in semi-solid culture at 5 days of cultivation time. During the whole period of cultivation with soluble starch, the extracellular glucoamylase activity of YW-112 was higher than that of the parental strain Yang no. 2. In addition, when 17 g/plate of rod-shaped yam bean was used instead of soluble starch, the protease-negative mutant strain YW-112 produced 490 g/l of citric acid, which is approximately 1.5 times as much citric acid as Yang no. 2 produced and showed enhanced extracellular glucoamylase production.

Production of citric acid from corncobs by Aspergillus niger

Corncobs could serve as a substrate for citric acid production by Aspergillus niger. Methanol had a significant effect on fungal production of citric acid from corncobs. Of the four cultures examined, A. niger NRRL 2001 was found to produce the highest amount of citric acid (250 g/kg dry matter of corncobs) after 72 h of growth at 30°C in the presence of 3% methanol. The yield of citric acid was over 50% based on the amount of sugar consumed.

Carob pod: a new substrate for citric acid production by Aspergillus niger.

The production of citric acid from carob pod extract by A. niger in surface fermentation was investigated. A maximum citric acid concentration (85.5 g/L), citric acid productivity (4.07 g/L/d), specific citric acid production rate (0.18 g/g/d), and specific sugar uptake rate (0.358 g/g/d) was achieved at an initial sugar concentration of 200 g/L, pH of 6.5, and a temperature of 30 degrees C. Other kinetic parameters, namely, citric acid yield, biomass yield, specific biomass production rate, and fermentation efficiency were maximum at pH 6.5, temperature 30 degrees C, and initial sugar concentration 100 g/L. The external addition of methanol into the carob pod extract at a concentration up to 4% (v/v) improved the production of citric acid.

Citric acid production by solid-state fermentation in a packed-bed reactor using Aspergillus niger

Kumara, a starch-containing root crop grown extensively in New Zealand, has been used as a substrate for citric acid production using Aspergillus niger in solid-state fermentation. When the process was operated in a packed-bed reactor, the bed loading was the most important operational parameter. The airflow rate and substrate particle size were also important but their net effects varied depending on other parameters; thus, a high airflow rate was conducive to citric acid production except under certain operating conditions (e.g., large substrate particle size) where it appeared to inhibit fungal growth possibly due to shear stress. A kinetic analysis of the system showed an overall reactor productivity of 0.82 g citrate kg −1 wet weight kumara h −1 which is twice that observed in flask culture. In this respect, the results in the packed-bed reactor were superior to published results in flask culture probably due to the improved aeration that was achieved.

Pineapple waste - a novel substrate for citric acid production by solid-state fermentation

Citric acid production in solid-state fermentation by Aspergillus foetidus ACM3996 was better on pineapple waste than on apple pomace, wheat bran or rice bran. The highest citric acid content achieved on pineapple waste was 16.1 g per 100 g dried pineapple waste, with a moisture content of 70% and in the presence of 3% methanol. This represents a yield of 62.4% based on the sugar consumed.

Fermentation of orange processing wastes for citric acid production

AbstractPress liquor from the dewatering of orange peel was used as a substrate for citric acid production. Of the three strains of Aspergillus niger examined, strain NRRL 599 produced the greatest amount of citric acid. The conditions favouring citric acid production were pH 5.0—6.2 in the presence of 40 ml kg−1 methanol. Under these conditions 30 g of citric acid per kg of press liquor were produced, representing a yield of 630 g kg−1 based on sugars consumed. The yield was further increased to 730 g kg−1 by thermal pretreatment of the press liquor.

Fermentation of kraft black liquor for the production of citric acid by Candida tropicalis

The production of citric acid by batch fermentation with the yeast strain Candida tropicalis ATCC 20240 was chosen as a potential process for the valorization of kraft black liquor. The effect of nitrogen concentration was studied and direct bioconversion of acetate to citrate was achieved when no nitrogen was supplemented to the medium. The use of kraft black liquor's acetate as a potential substrate for citric acid production was investigated. The acid precipitated liquor was highly inhibitory when its concentration was above 25% of the fermentation broth content. The yields of citric acid at low concentrations of kraft black liquor (5% and 15%) were the same as those recorded in synthetic acetate medium. Other organic acids present in the liquor may affect the yields and rates of citric acid production over acetate. Substrate uptake rates and product formation rates were lower, however, in comparison to synthetic media. The utilization of immobilized biomass improved the process parameters on kraft black liquor and enhanced the fermentation capabilities.

Grape pomace: A novel substrate for microbial production of citric acid

Apple pomace, the residue left from juice extraction, can be employed as a substrate for citric acid production using Aspergillus niger as the fermentation agent.