Cultures Of Aspergillus Niger Research Articles

Soybean molasses as a new and low-cost substrate for gluconic acid production by Aspergillus niger

Soybean molasses (SM), a sugar-rich by-product obtained from manufacturing soy protein concentrate, is an interesting source of fermentable sugars for biotechnological processes. For the first time, SM was used as a new and low-cost substrate in Aspergillus niger cultures to produce gluconic acid (GA), a carboxylic acid obtained by the oxidation of glucose and with a wide range of applications. The effect of SM composition and sugar content on GA batch production was studied in a stirred-tank bioreactor using two SM samples with different total sugar concentrations of 46 % and 52 % (w/w) and different sugar profiles. GA productivity improved as the total sugar concentration increased, whereas yield was unaffected. Agitation rate increase positively affected yield and productivity in SM medium with the highest sugar concentration. Under these conditions, the highest GA titer (79 g·L−1) was obtained. Oxalic acid and fructose syrup were other added-value compounds found from the submerged fermentation of SM. This work proved the potential of A. niger in the bioconversion of SM with different compositions into GA, providing a novel strategy for low-cost and eco-friendly GA production from SM.

Peptide derived from plant defensins: A promising 68Ga radiolabelled agent for diagnostic of infection foci in PET.

The development of new radiopharmaceuticals for the detection of hidden infection foci has great relevance for early detection and the selection of the correct treatment, particularly in immunosuppressed patients. In that sense, the labelling of antimicrobial peptides (AMPs) that are capable of binding specifically to the pathogenic microorganism which causes the infection, should provide a sufficiently specific agent, able to distinguish an infection from a sterile inflammation. Defensins are particularly interesting molecules with antimicrobial activity, the EcgDf1 defensin was identified from the genome of a Uruguayan native plant, Erythrina crista-galli, the 'Ceibo' tree. Our group has previously reported a synthetic biologically active short analogue EcgDf21 (ERFTGGHCRGFRRRCFCTKHC) successfully labelled with 99mTc. Herein we present a shorter analogue which also preserves the γ-core domain, as a pharmacophore for a potential infection detection agent. This peptide was derivatized with the bifunctional chelating agent 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) through a lysine linker in the amino-terminal group (NOTA-KGHCRGFRRRC) and radiolabelled with 68Ga ([68Ga]Ga-NOTA-K-EcgDf1(10)). The [68Ga]Ga-NOTA-K-EcgDf1(10) labelling procedure rendered a product with high radiochemical purity and stability in the labelling milieu. The Log P value indicated that the complex has a hydrophilic behaviour, confirmed by the biodistribution profile. The [68Ga]Ga-NOTA-K-EcgDf1(10) complex demonstrated specific binding to cultures of Candida albicans and Aspergillus niger. Its biodistribution showed renal elimination and low accumulation in the rest of the body. It was possible to successfully differentiate sterile inflammation from infection by PET images in nude mice with a target/non-target ratio of 3.3 for C. albicans and 3.7 for A. niger, respectively.

Uncovering the nutraceutical potentials of fermented sago starch “Lemantak” by endophytic fungi

Fermentation food has been widely consumed since ancient times due to its many beneficial properties as well as improved texture and taste. Raw sago starch “lemantak” (RSS “lemantak”) is one of the staple foods in the state of Sarawak. Derived from the bark of Metroxylon sagu, this starch has yet to be investigated in terms of its phytochemical and nutraceutical properties after being subjected to fermentation. This study investigated the nutraceutical of fermented RSS “lemantak” in its phenolic content and antioxidant activity in different fermentation conditions by selected endophytic fungi, Aspergillus niger, Penicillium chermesinum and Fusarium equiseti. This study compared two different fermentation modes and also investigated phenolic production by manipulating the fungal consortia, incubation period as well as the solvent used. It was determined that the best endophyte culture was consortia of Aspergillus niger and Penicillium chermesinum under solid state fermentation (SSF) while monoculture Aspergillus niger was the best fungal culture under SMF. It was found that the dual cultures of Aspergillus niger and Penicillium chermesinum (AP) showed high total phenolic content of 174.95 mg GAE/g and high antioxidant activity at different concentrations ranging from 90.21-76.17% under solid-state fermentation at day 7. In contrast, under submerged fermentation, it was found that consortia of Aspergillus niger and Penicillium chermesinum produced low phenolic content of 11.54 mg GAE/g and had lower antioxidant capacity with the range values of 39.26-34.03%. On the other hand, monoculture Aspergillus niger strives best under SMF at 203.65 mg GAE/g and has good antioxidant activity of 90.72-14.15% of scavenging activity. Nevertheless, it was determined that the dual culture of AP showed high potential based on the phenolic content antioxidant activity under SSF while monoculture A. niger showed potential as a phenolic content producer and antioxidant activity. This study ascertained that the best conditions for fermented RSS “lemantak” with higher phenolic content and antioxidant properties are the methanol extract of fermented RSS inoculated with dual cultures Aspergillus niger and Penicillium chermesinum for a period of 7 days of incubation under SSF.

Metabolic profiling, antimicrobial, anticancer, and in vitro and in silico immunomodulatory investigation of Aspergillus niger OR730979 isolated from the Western Desert, Egypt.

Ten fungal species were isolated from soil in the Western Desert and Wadi El-Natron in Egypt. All fungal isolates were morphologically recognized down to the species level. Methanol extracts of fungal mycelia and ethyl acetate extracts of culture filtrate from the isolated fungi were evaluated for antimicrobial activity against six pathogenic bacteria and one pathogenic yeast (Candida albicans ATCC20231). Only ethyl acetate extracts of Fusarium circinatum, Aspergillus niger, and Aspergillus terreus culture filtrates showed significant antimicrobial activity against the majority of the investigated pathogens. The culture filtrate extract of Aspergillus niger exhibited notable cytotoxicity towards the breast cancer (MCF-7) cell line, with the lowest detected IC50 recorded at 8 μg/μl. Whereas Fusarium circinatum and Aspergillus terreus had IC50s of 15.91 μg/μl and 18 μg/μl, respectively. A gas chromatography-mass spectroscopy (GC-MS) investigation of A. niger's potent extract revealed 23 compounds with different biological activities. Glycidyleoleate was found to be the main extract component. Aspergillus niger extract was chosen to study its possible cytotoxic mechanism. The extract was found to induce apoptosis and cell cycle arrest at the < 2n stage. Despite a significant increase in caspases 8 and 9, the production levels of tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) have shown a significant decrease. The high interaction of glycidyleoleate against the studied cytokines' binding receptors was demonstrated via docking studies. In conclusion, the available data revealed that the culture filtrate extract of A. niger possesses promising antimicrobial, cytotoxic, and immunomodulatory properties.

Rare Earth Extraction from Phosphogypsum by Aspergillus niger Culture Broth.

The extraction of rare earth elements (REEs) from phosphogypsum (PG) is of great significance for the effective utilization of rare earth resources and enhancing the resource value of PG waste residues. This study used Aspergillus niger (A. niger) fungal culture filtrate as a leaching agent to investigate the behavior of extracting REEs from PG through direct and indirect contact methods. According to the ICP-MS results, direct leaching at a temperature of 30 °C, shaking speed of 150 rpm, and a solid-liquid ratio of 2:1, achieved an extraction rate of 74% for REEs, with the main elements being yttrium (Y), lanthanum (La), cerium (Ce), and neodymium (Nd). Under the same conditions, the extraction rate of REEs from phosphogypsum using an A. niger culture filtrate was 63.3% higher than that using the simulated organic acid-mixed solution prepared with the main organic acid components in the A. niger leachate. Moreover, the morphological changes observed in A. niger before and after leaching further suggest the direct involvement of A. niger's metabolic process in the extraction of REEs. When compared to using organic acids, A. niger culture filtrate exhibits higher leaching efficiency for extracting REEs from PG. Additionally, using A. niger culture filtrate is a more environmentally friendly method with the potential for industrial-scale applications than using inorganic acids for the leaching of REEs from PG.

The Potential of Fungal Biomass as Agents for Biosorption of Chromium (VI) Ion from Tannery Effluent

Biosorption and bioaccumulation are the overall process by which microorganism tolerate toxic levels of heavy metals in the environment. Thus, filamentous fungi are able to accumulate significant amount of metals from their environment. The potential of fungal biomass as agents for biosorption of chromium (VI) ion from tannery effluent is currently receiving attention. In the present study a total of four isolate of filamentous fungi and Candida sp, were obtained from tannery effluent Mario Jose locate at Challawa industrial estate Kano. These fungi were characterized morphologically, microscopically and screened for their tolerance and uptake capability of chromium (VI) ion in medium. The isolates were identified as viz; Rhizopus nigrican Aspergillus niger and Penicillium sp. Only three of these species were able to survived at 4% concentration of chromium ion solution on modified rice husk medium (MRHM). The results showed that Rhizopus nigricans and Aspergillus niger have better uptake capacity for chromium (VI) ion by these filamentous fungi from aqueous solution. The present study was also determined the maximum removal of chromium (VI) ion that performed by Rhizopus nigricans, Aspergillus niger, Penicillium sp and mixed culture organisms. The chromium (VI) removal with initial concentration ranging from 1.517mg/l – 0.067, 1.517mg/l – 0.072mg/l and Penicillium sp 1.517mg/l – 0.73mg/l and mixed culture 1.517mg/l – 0.874mg/l. The above studies show Rhizopus nigricans and Aspergillus niger organisms appear to be more effective in biosorption of Cr6+ in effluent using modified agricultural waste in comparison with conventional one’s base on time duration of absorption.

Fungal bioleaching of metals from WPCBs of mobile phones employing mixed Aspergillus spp.: Optimization and predictive modelling by RSM and AI models

In the present study, optimization and prediction models for fungal bioleaching for effective metal extraction from waste printed circuit boards (WPCBs) of mobile phones were developed employing central composite design (CCD) of response surface methodology (RSM), and two artificial intelligence (AI) models, i.e., artificial neural network (ANN) and, support vector machine (SVM), respectively. Two continuous process parameters, such as pH (4–9) and pulp density (1–10 g/L), and the bioleaching approaches, viz., one-step and two-step, were experimentally optimized for the extraction of targeted metals, i.e., Cu, Ni, and Zn from WPCBs by mixed cultures of Aspergillus niger and Aspergillus tubingensis. Datasets were then used for predictive modelling using AI tools. Results showed that the highest simultaneous bioleaching of Cu, Ni, and Zn, with an extraction efficacy of about 86%, 51%, and 100%, respectively, achieved at an optimal condition of pH 5.7 and pulp density of 3 g/L following the two-step bioleaching approach. Effective metal extraction in the two-step approach could be attributed to the abundant production of organic acids with a content of about 16.3 g/L, 8.4 g/L, and 0.5 g/L of citric acid, oxalic acid, and malic acid, respectively. Further, the predictive modelling revealed that the ANN model was found to predict the fungal bioleaching responses more accurately as compared to the SVM model with R2 values exceeding 0.96 for all targeted metals. This research demonstrates the applicability of the optimization and prediction models for efficient metal extraction from WPCBs using mixed Aspergillus spp. following the two-step approach.

Extracellular Zn Detoxication by &lt;i&gt;Penicillium chrysogenum&lt;/i&gt; and &lt;i&gt;Aspergillus niger&lt;/i&gt;

Microfungi are promising objects for bioremediation due to their ability to convert metals into forms that are less mobile and accessible to organisms. The study showed that the fungi Penicillium chrysogenum and Aspergillus niger have physiological mechanisms of extracellular Zn detoxification at its initial concentration of 250 µmol – 2 mmol in the medium. At concentrations of 250–500 µmol Zn promotes the accumulation of biomass and abundant sporulation of A. niger and Penicillium chrysogenum, and at concentrations of 1–2 mmol inhibits the growth of fungi. Extracellular Zn detoxification in Aspergillus niger culture occurs by the formation of dihydrate zinc oxalate katsarosite, due to the active biosynthesis of oxalic acid in A. niger. The main mechanism of zinc detoxification in Penicillium chrysogenum culture was the formation of zinc phosphate hopeite. The formation of zinc phosphate hopeite under the action of the fungus was established for the first time. The key factors that determine the direction of the processes of formation of extracellular mineral phases are the amounts of EPS and oxalic acid produced by fungi, as well as changes in the pH of the medium during the growth of cultures.

Comparative Evaluation of Unpeeled Cassava (Manihot esculenta) and Tacca (Tacca involucrata) Tuber Flours as Substrates for Bioethanol Production

The ever-increasing demand for alternatives to fossil fuel due to its negative impacts on the environment and high prices have resulted in the search for feedstock for bioethanol production. Cassava is one of the major staple foods that is processed into various preservative forms in Nigeria, while tacca is a plant growing in the wild and is eaten by a few people during scarcity of food. Unpeeled cassava and tacca tubers were processed into flour. The flour was hydrolyzed using Aspergillus niger and Saccharomyces cerevisiae, separately. The bioethanol potentials of tuber flours were evaluated using a single-step process. Hydrolysis of 10g of cassava tuber flour separately by Aspergillus niger and Saccharomyces cerevisiae produced (g/100mL) 0.720 and 0.765 of sugar, respectively, while hydrolysis of 10g of tacca tuber flour separately by Aspergillus niger and Saccharomyces cerevisiae produced (g/100mL) 0.392 and 0.367 of sugar respectively. Evaluation of the effect of time during hydrolysis of cassava tuber flour for 24h by Aspergillus niger and Saccharomyces cerevisiae separately produced (g/100mL) 1.44 and 0.737 of sugar, while hydrolysis of tacca tuber flour for 24h produced (g/100mL) 0.768 and 0.493 of sugar. Evaluation of the effect of varying pH values during hydrolysis of the tuber flours revealed that pH 5.6 produced the highest concentration of sugar (0.240g/100mL) and (0.803g/100mL) when Aspergillus niger and Saccharomyces cerevisiae were separately used to hydrolyze cassava tuber flour. When Aspergillus niger and Saccharomyces cerevisiae were separately used to hydrolyze tacca tuber flour at pH 5.6, 0.626g and 0.436g of sugar was produced. Fermentation of cassava tuber flour by mixed culture of Aspergillus niger and Saccharomyces cerevisiae for 48h produced 3.851%(w/v) bioethanol at 24h of fermentation, while fermentation of tacca tuber flour by mixed culture of Aspergillus niger and Saccharomyces cerevisiae produced 3.236% (w/v) bioethanol at 48h. Cassava tuber flour produced a higher concentration of bioethanol than tacca tuber flour. These results have shown that tacca tuber is a potential feedstock for bioethanol production, hence exploitation of nonfood materials such as tacca tuber for bioprocesses can reduce the over _dependence on cassava tuber.

Green synthesis, antibacterial and antifungal evaluation of new thiazolidine-2,4-dione derivatives: molecular dynamic simulation, POM study and identification of antitumor pharmacophore sites

In this study, a series of thiazolidine-2,4-dione derivatives 3a–i were synthesized and evaluated for antibacterial activity against Gram-positive and Gram-negative strains of Bacillus licheniformis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Newly prepared thiazolidine (TZD) derivatives were further screened separately for in vitro antifungal activity against cultures of fungal species, namely, Aspergillus niger, Alternaria brassicicola, Chaetomium murorum, Fusarium oxysporum, Lycopodium sp. and Penicillium notatum. The electron-donating substituents (–OH and –OCH3) and electron-withdrawing substituents (–Cl and –NO2) on the attached arylidene moieties of five-membered heterocyclic ring enhanced the broad spectrum of antimicrobial and antifungal activities. The molecular docking study has revealed that compound 3h strongly interacts with the catalytic residues of the active site of the β-carbonic anhydrase (P. aeruginosa) and has the best docking score. In silico pharmacokinetics studies showed the drug-likeness and non-toxic nature of the synthesized compounds, which indicates the combined antibacterial, antiviral and antitumor pharmacophore sites of the targeted drug. This work demonstrates that potential TZD derivatives bind to different types of bacterial and fungal pathogens for circumventing their activities and opens avenues for the development of newer drug candidates that can target bacterial and fungal pathogens. Communicated by Ramaswamy H. Sarma

Potential of Fungal-Microalgal species in the Environmental Biotechnology

Biotechnology involves the provision of services to society by microbial communities. By using microorganisms to detoxify contaminated water, one such service offers environmentally friendly solutions to the treatment of wastewater. Isolates of fungi Aspergillus niger, Candida albicans and microalgal isolates Tetradesmus nygaardi and Scenedesmus quadricauda were efficiently utilized for the treatment of wastewater. The wastewater sample was taken from Erbil wastewater channel near Dhahibah village, the sample was analyzed for physicochemical parameters such as pH, EC, TDS, BOD5, PO4, NH4, NO3, and NO2 (every 3rd day) during 21 days of experiment. Results revealed that a mixed culture of S. quadricauda with T. nygaardi were shows the best removal of PO4, NH4, NO3 and NO2 in which 94.94%, 90.73%, 88.23%, 93.84% respectively. Whereas a mixed culture of T. nygaardi with A. niger showed the best removal of BOD5 (94.9%), while the highest reduction in electrical conductivity and total dissolved solid were recorded by mix culture of Aspergillus niger with Candida albicans 81.65% and 81.52%. Statistically, there were a significant difference (p≤0.05) between control and all microbial stains for all wastewater tested variables.

Heterogeneity in Spore Aggregation and Germination Results in Different Sized, Cooperative Microcolonies in an Aspergillus niger Culture.

The fungus Aspergillus niger is among the most abundant fungi in the world and is widely used as a cell factory for protein and metabolite production. This fungus forms asexual spores called conidia that are used for dispersal. Notably, part of the spores and germlings aggregate in an aqueous environment. The aggregated conidia/germlings give rise to large microcolonies, while the nonaggregated spores/germlings result in small microcolonies. Here, it is shown that small microcolonies release a larger variety and quantity of secreted proteins compared to large microcolonies. Yet, the secretome of large microcolonies has complementary cellulase activity with that of the small microcolonies. Also, large microcolonies are more resistant to heat and oxidative stress compared to small microcolonies, which is partly explained by the presence of nongerminated spores in the core of the large microcolonies. Together, it is proposed that heterogeneity in germination and aggregation has evolved to form a population of different sized A. niger microcolonies, thereby increasing stress survival and producing a meta-secretome more optimally suited to degrade complex substrates. IMPORTANCE Aspergillus niger can form microcolonies of different size due to partial aggregation of spores and germlings. So far, this heterogeneity was considered a negative trait by the industry. We here, however, show that heterogeneity in size within a population of microcolonies is beneficial for food degradation and stress survival. This functional heterogeneity is not only of interest for the industry to make blends of enzymes (e.g., for biofuel or bioplastic production) but could also play a role in nature for effective nutrient cycling and survival of the fungus.

New Bicyclic Lactone by Biotransformation of β-caryophyllene using Aspergillus niger

Abstract: Microbial transformation of β-caryophyllene (1) by suspended cell cultures of the plant pathogen fungus Aspergillus niger, resulted in the production of one major metabolite. This metabolite was identified as (3aR,11aS, E)-9-methyl-4-methylene-3a,4,7,10,11,11a-hexahydro-2H-furo[3,2- c]oxecine-2,6(3H)-dione (2), by different spectroscopic methods. Metabolite 2 was found to be a new compound. The proposed pathway for the synthesis of compound 2 was also explained.

Application of two fungal strains Aspergillus niger and Candida albicans in wastewater quality improvement

The nutrients Phosphorous, Nitrogen and Carbon are essential for aquatic life. However, in excess they also cause serious problems. For this reason, wastewater treatment must meet nutrient effluent limits. A wastewater sample was taken near Dhahibah village from the Erbil wastewater channel in the north of Iraq. In this experiment, pure cultures of Aspergillus niger and Candida albicans were used to treat wastewater. Samples were measured for physicochemical parameters like EC, pH, Phosphate, Nitrate, Nitrite, and BOD5 using standard methods every third day during 21 days of experiment. The results revealed that Aspergillus niger had the maximum efficiency in removing BOD5, NH4, NO3, and EC (87.27, 89.57, 83.52, and 78.49%) respectively. On the other hand, during the experimental period, Candida albicans had the maximum efficiency in decreasing PO4, and NO2, were (91.58% and 88.89%), respectively. Statistically, there were differences (P≤0.05) between the control sample and the treated wastewater sample for both fungal stains for all parameters during the experiment.

Optimization and application of UVC irradiation for prevention of fungal biodeterioration of vegetable tanned and chrome tanned leather

UV-C irradiation critically effects the growth of micro-fungi and also deteriorate leather materials. In the present study vegetable tanned and chrome tanned leather were infected with pure cultures of Aspergillus niger and Aspergillus flavus, which were isolated from stored leather materials. UV-C light (λ = 254 nm) was applied on infected leather for 15 and 60 min. The changes in leather qualities were examined through weight, tensile strength, scanning electron microscope, energy dispersive X-ray and Fourier transform infrared spectroscopy study after 15 and 30 days of fungal inoculation. Vegetable tanned leather was more vulnerable in case of fungal attack than chrome tanned leather while A. flavus showed more influence on leather deterioration than A. niger. The results showed that weight loss after 30 days for 15 and 60 min irradiation exposure was 1.3% compared to A. flavus infected leather (3.93%). The tensile strength of vegetable and chrome tanned UV irradiated leather was increased by 44% and 7% respectively. The scanning electron microscopic images exhibit the limited presence of conidiophores in UV-C exposed leather which confirmed the potentiality of irradiation for controlling fungal growth. The infrared spectral analysis of UV-C exposed infected leather samples showed neither shifting of wavenumber nor displacement of any functional groups. Altogether the efficacy of UV-C irradiation against biodeterioration of leather was concluded to be effective. This method can be used to control fungal growth without compromising the leather quality.Graphical

UTILIZATION OF AGRICULTURAL WASTE AS A SUBSTRATE FOR PRODUCING CELLULASE ENZYME BY ASPERGILLUS NIGER

Fresh Fruit Bunches (FFB) of oil palm, bran, straw, and bagasse are agricultural wastes whose availability is very abundant in Indonesia. The agricultural waste is lignocellulosic waste which still has economic value if further processing is carried out, namely as a substrate in the production of cellulase enzymes. Cellulase enzymes are commonly used in various industries such as food biotechnology, textiles, animal feed, paper, and agriculture to degrade cellulose with its main products, namely glucose, cellobiose, and cellooligosaccharides. In producing cellulase enzymes, it is necessary to have microorganisms that have a high ability to produce enzymes, one of which is Aspergillus niger. The purpose of this study was to determine the activity of crude cellulase enzyme, protein content, and specific activity of cellulase enzyme from agricultural waste which includes FFB, bran, straw, and bagasse. The research methods included preparation of Aspergillus niger culture, delignification, basal medium preparation, cellulase enzyme production, enzyme extraction, crude cellulase enzyme activity test (CMC-ase), lowry method protein content test, and determination of cellulase enzyme specific activity. The study showed that the highest crude cellulase enzyme activity in bran was 26.83 U/ml, the highest protein content in bagasse was 63.42 g/ml, and the highest specific activity of cellulase enzyme in straw was 0.9818 U/ml. The high enzyme activity is influenced by the cellulose content in the material, type of substrate, media, substrate concentration, pH, and temperature.

Assessment of Simple Methods to preserve Pure Cultures of Aspergillus Versicolor and Aspergillus Niger

The preservation of pure fungal cultures is considered as an important part of applied and industrial microbiology applications. In this study, we are focusing on filamentous fungi preservation as these species are very useful in industrial applications such as wastewater treatment, biofuel production etc. We are presenting an evaluation of three methods to maintain and preserve filamentous fungi: refrigeration on filter paper, refrigeration with glycerol and cryopreservation with DMSO. The three methods were tested on the pure cultures of Aspergillus versicolor and Aspergillus niger. The three methods were successful where the viability measured by colony forming unit CFU counts was confirmed. We suggest that for the short-term preservation of filamentous fungi, the filter paper method could be preferred as it is very simple, quick and effective.

The Effect of Some Components Changes of Aspergillus niger Culture Media on the Production of Lipase Enzyme

The current work aimed to study the effect of some component changes of Aspergillus niger culture media on the production of lipase enzyme. Media contained nitrogenous sources, ammonium nitrate, peptone, nitrate phosphate, mono-potassium phosphate, and aqueous magnesium sulfate. It was found that the isolation was unable to grow and produce lipase enzyme efficiently due to the presence of inorganic nitrogen sources. The highest value of the dry weight rate was realized while using ammonium chloride at concentration of 1.23 g/100 ml. Ammonium nitrate was the best source (treatment) compared to the rest of the sources at a concentration of 0.1 g/100 ml, where the dry weight was 1.28 g/100 ml, and the effectiveness of lipase was 22.86 U/ml. Adding peptone with the ammonium nitrate to the medium helped to raise the productivity of isolated fungus, where the dry weight reached 2.75 g/100 ml, while the lipase activity reached 36.93 U/ml. The biomass in the organic nitrogen sources medium reached (2.24 g/100 ml). The highest value of the dry weight of phosphate source media (KH2PO4) reached (2.87 g/100 ml) at a concentration (0.28 g/100 ml), achieving the best value of the lipase’s effectiveness (39.96 U/ml). Aqueous magnesium sulfate concentration media resulted in a sort increase in the fungus isolation biomass, as the highest biomass for aqueous magnesium sulfate media was (3.00 g/100 ml) at (0.05 g/100 ml) concentration.

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&lt; 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.

Evaluating the potential of wild cocoyam (Caladium bicolor) for citric acid production in a submerged culture of Aspergillus niger

BackgroundWild cocoyam (Caladium bicolar) is non-edible starchy material which is commonly known as ‘Ede umuagbara’ in the south-east region of Nigeria. Evaluating the potential of wild cocoyam for citric acid production was investigated using Aspergillus niger in a submerged culture.ResultsThis study showed that wild cocoyam flour concentration, pretreatment of wild cocoyam, inoculums size, initial pH of wild cocoyam and incubation temperature of wild cocoyam medium had significant effect on the amount of citric acid produced from wild cocoyam (p < 0.05). Citric acid concentration increased as the concentration wild cocoyam increased up to 15% with the maximum citric acid concentration of 10.0 ± 0.251 g/l after 96 h of fermentation. Also citric acid concentration increased as the pretreatment time of wild cocoyam increased from 5 to 20 min. A 20 min pretreatment time at 121 °C was the optimum with maximum concentration of 14.0 ± 0.325 g/l citric acid after 96 h of fermentation. 15% inoculums was the optimum with the maximum concentration of 16.0 ± 0.431 g/l citric acid. However, the wild cocoyam initial pH value of 5.5 was the optimum for maximum citric acid concentration of 19.0 ± 0.316 after 96 h of fermentation. Moreover, citric acid concentration increased as the incubation temperature of wild cocoyam medium increased from 20 to 30 °C. Incubation of wild cocoyam medium at 30 °C was the optimum with the maximum citric acid concentration of 23.0 ± 0.432 g/l after 96 h of fermentation.ConclusionTherefore, the result revealed that wild cocoyam which is found plenty within the south-east region of Nigeria can be converted to citric acid if well harnessed.