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.
1 November 2018 in South African Journal of Botany
Indigenous and non-commercial fruits can be an important source of antioxidant polyphenols; however, the identity and content of polyphenols from non-commercial fruits are often poorly described. The study aimed to extract, identify, and quantify polyphenols from the skin of the indigenous Africa fruit Ximenia caffra, using solvent extraction. Three solvents (hexane, acetone, and 70% v/v ethanol) over three extraction times (30, 60 and 120 min) were used in a 32 full factorial experimental design to determine effects on polyphenol recovery, and individual polyphenolics were characterised using liquid chromatography high-resolution mass spectrometry (LC-HRMS). Ethanol was the most effective extraction solvent, and extracts had high levels of total phenolics and flavonoids (65 mg gallic and 40 mg catechin equivalents per gram dry sample respectively), and high antioxidant activity (18.2 mg mL−1 ascorbic acid equivalents). LC-HRMS positively identified 16 compounds, of which 14 were flavonoids including flavonoid glycosides, and indicated that concentrations of some flavonoids decreased for extraction times beyond 60 min. It was concluded that the fruit of Ximenia caffra is rich in natural polyphenolic antioxidants; the present work identified and quantified a number of these, while also establishing suitable solvent extraction conditions for the recovery of these potentially high-value compounds.
The microbial contribution to soil organic matter has been shown to be much larger than previously thought and thus it plays a major role in carbon cycling. Among soil microorganisms, chemoautotrophs can fix CO2without sunlight and can glean energy through the oxidation of reduced elements such as sulfur. Here we show that the addition of sulfur to soil results in an initial surge in production of CO2through microbial respiration, followed by an order of magnitude increase in the capture of carbon from the atmosphere as elemental sulfur is oxidised to sulfate.Thiobacillus spp., take advantage of specific conditions to become the dominant chemoautotrophic group that consumes CO2. We discern the direct incorporation of atmospheric carbon into soil carbohydrate, protein and aliphatic compounds and differentiate these from existing biomass. These results suggest that chemoautotrophs can play a large role in carbon cycling and that this carbon is heavily influenced by land management practises.
The aim of study was to evaluate the antibacterial activity of Cochlospermum tinctorium against ten (10) strains of antibiotic resistant food-borne pathogens Staphylococcus aureus and Listeria monocytogene. Ten (10) strains of antibiotic resistant food-borne pathogens Staphylococcus aureus and Listeria monocytogene procured from Microbiology Research Laboratory Usman Danfodiyo University Sokoto. The roots of Cochlospermum tinctorium were collected from the rock side in Dambu Gomo, Zuru Local Government Area of Kebbi State, Nigeria. The roots were washed, air-dried and milled to powder using mortal and pestle and sieved to obtained fine powder. Maceration was used for extraction using methanol as solvent. The antibacterial activity of the plant was determined on Mueller Hinton agar using agar well diffusion method. Minimum concentration (MIC) and minimum inhibitory concentration (MBC) of plant extract was also determined. Thin layer chromatography and column chromatography was employed for separation and fraction of different compounds in the plant extract. The fractions were screened for antibacterial activity and active fractions having high antibacterial activity were subjected Gas Chromatography Mass Spectoscopy (GC-MS) analysis. The result of methanol extraction yield 5.17% extracts. The methanol extract of Cochlospermum tinctorium was effective in inhibiting the isolates at high concentration of 10 mg/mL. The results thin layer chromatography revealed four spots with Rf values 0.02, 0.37, 0.44 and 0.80 respectively. The GC-MS analysis of the active methanol extract of Cochlospermum tinctorium root powder revealed the existence of major peaks 1-(+)-Ascorbic acid 2,6-dihexadecanoate (R.T: 13.666), Diethyl phthalate (R.T: 10.440), Undecyl acetate (R.T: 10.007), 3-tetradecanone (R.T: 9.793), 3-hexadecanone (R.T: 12.427). It therefore concluded that the root of Cochlospermum tinctorium has immense potential to be used in the area of pharmacology as it possess antimicrobial activity against the antibiotic resistant food-borne pathogens, thus could be exploited as alternative antimicrobial drugs.