Ethanol production from corn cobs by co-culture of Saccharomyces cerevisiae and Aspergillus niger

Saccharomyces cerevisiae and Aspergillus niger were used in a co-culture for the simultaneous saccharification and fermentation (SSF) of 1% and 10% (w/v) dry pre-treated corn cobs to ethanol. Positive controls of glucose of same concentrations in a synthetic medium were also fermented. At 1% substrate concentration, the complex medium containing corn cobs had a maximum ethanol yield of 4.17%, while the synthetic medium with glucose gave 3.45%. At a higher concentration of 10% the synthetic medium gave a yield of 6.23% which is comparable to 6.17% by the complex medium. Residual sugar concentration was observed to decrease with increase in ethanol production and cell growth increased with time of fermentation. Keywords: Saccharomyces cerevisiae, Aspergillus niger, corn cobs, glucose, ethanol

Screening and Improvement of Local Isolates of Aspergillus Niger for Citric Acid Production

The study involved the screening of fourteen isolates of Aspergillus niger for citric acid production from glucose. The study was aimed at screening and improving local strains of Aspergillus niger with potential for citric acid production. All the isolates screened produced varying amounts of citric acid, the highest was by the isolate designated CP3 which produced 12.81g/l and the least was B11 and O12 which produced 3.42g/l all after 6 days of submerged fermentation. The isolate CP3 was chosen for further studies. Strain improvement studies which was based on exposure of CP3 to ultraviolet irradiation for 10, 30 and 45 minutes increased citric acid yield to 22.20g/l (48.89% increase) by mutant M45 followed by a citric acid yield of 16.22g/l by the 30 minutes mutant (M30) and the least being M10 which produced 13.66g/l in all cases after 6 days of fermentation. The mutant (M45) also yielded higher amount of citric acid (19.64g/l) without methanol as additive compared to the parent strain (CP3) which gave a citric acid of 14.94g/l with the addition of methanol after six days (144h) of fermentation in both cases. Finding from this study showed that all the isolates have potential for citric acid production.Keywords: Isolation, Screening, Improvement, Aspergillus niger, Citric aci

Comparative Study on The Potency of Antibiotic Discs With Commercially Sold Antibiotics on Clinical Isolates From Urinary Tract

A total of 250 urine samples were collected from patients attending Ahmadu Bello University Health Service Clinic (Sick bay), Salama Hospital and Major Ibrahim Abdullahi Memorial Hospital (Kaduna State Ministry of Health). The samples were screened for UTI and forty-three (43) were positive for Klebsiella and Escherichia coli. Of all the isolates, 24 were K. species and 19 were Escherichia coli. Their susceptibilities to Ampicillin, Ciprofloxacin and Gentamicin were examined using the antibiotics disc and the commercially sold antibiotics. The susceptibility of K. species to Ampicillin, Ciprofloxacin and Gentamicin for the antibiotics disc was 16.7%, 62.5% and 41.7% respectively. For the commercially sold antibiotics its susceptibility was 0%, 8.3% and 50.0% to Ampicillin, Ciprofloxacin and Gentamicin respectively. The susceptibility of Escherichia coli to Ampicillin, Ciprofloxacin and Gentamicin for the antibiotics disc was 31.6%, 52.6% and 57.9% respectively. For the commercially sold antibiotics its susceptibility was 0%, 36.8% and 31.6% to Ampicillin, Ciprofloxacin and Gentamicin respectively. Our results showed that antibiotics disc was more effective than the commercially sold antibiotics and that both organisms were resistant to Ampicillin but susceptible to Gentamicin and Ciprofloxacin.Keywords: Potency, Antibiotics, Disc Isolates, Urinary tractNigerian Journal of Basic and Applied Science (2011), 19(2):231- 23

Phytochemical and Antibacterial Properties of Leaf Extracts of Ipomoea asarifolia

The antibacterial potency of aqueous and methanol extracts of Ipomoea asarifolia leaves; a plant widely used by traditional medical practitioners in Nigeria was determined in vitro against three bacterial pathogens (Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa) by agar well diffusion method. The pattern of inhibition varied with the extracts and the organisms tested. Both the aqueous and methanol extracts were potent on E. coli and S. aureus with maximum zone of growth inhibition of 21mm and 20mm at 200mg/ml respectively Pseudomonas aeruginosa was resistant to both extracts at all the concentrations tested. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against E. coli for aqueous extract were 50mg/ml and 100mg/ml respectively; and 100mg/ml and 200mg/ml for methanol extract respectively. Similarly, The MIC and MBC against S. aureus for aqueous extract were 100mg/ml and 200mg/ml; 200mg/ml for the methanol extract. Preliminary phytochemical screening reveal the presence of anthraquinones, saponins and tannins in both aqueous and methanol extracts; triterpenes, flavonoids and glycosides were found only in the aqueous extract while alkaloids were found only in the methanol extract. However, carbohydrate and steroids were absent in both extracts. The spectra of activities shown by the extracts could be attributed to the presence of these phytochemicals which signifies the potential of I. asarifolia as a source of therapeutic agents. These findings therefore, justify the traditional medicinal use of the plant.Keywords: Ipomoea asarifolia, phytochemical, antibacterial potency, bacterial pathogensNigerian Journal of Basic and Applied Science (2011), 19 (2): 236-24

Asteroseismology and Interferometry

Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within Astrophysics and have led to a significant increase in the size of the research community. In the present paper we start by reviewing the basic observational and theoretical properties of classical and solar-like pulsators and present results from some of the most recent and outstanding studies of these stars. We centre our review on those classes of pulsators for which interferometric studies are expected to provide a significant input. We discuss current limitations to asteroseismic studies, including difficulties in mode identification and in the accurate determination of global parameters of pulsating stars, and, after a brief review of those aspects of interferometry that are most relevant in this context, anticipate how interferometric observations may contribute to overcome these limitations. Moreover, we present results of recent pilot studies of pulsating stars involving both asteroseismic and interferometric constraints and look into the future, summarizing ongoing efforts concerning the development of future instruments and satellite missions which are expected to have an impact in this field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume 14, Issue 3-4, pp. 217-36

Optimization of Citric Acid Production through Manipulation of Cultural Conditions of Aspergillus Niger

An Aspergillus niger isolate was screened for citric acid production from glucose and the cultural conditions were manipulated for optimum citric acid production. Optimization studies improved citric acid yield by 13.34% from 12.81 g/l obtained during the screening test to 14.52 g/l obtained at the end of the optimization studies. Glucose concentration of 15%, pH of 5.5, methanol at 3% concentration (v/v) and agitation rate of 450 rpm were found to be more suitable for citric acid production by the Aspergillus niger isolate used in this studies. Keywords: Citric acid, Aspergillus niger, Submerged fermentation, cultural condition

Effect of Planting Pattern and Irrigation Frequency on Forage Yield and Chemical Composition of Lablab (Lablab Purpureus (L.) Sweet) in Combination with Maize (Zea mays L.)

A study was conducted at Kadawa Experimental Research Station of the Institute for Agricultural Research Kano during the 2010/2011 dry season to determine forage yield of lablab, nutritive quality of lablab forage and maize grain yield using five (5) different planting patterns and three (3) irrigation frequencies. A 5 x 3 factorial experiment in a complete randomized block design with a split plot arrangement was used. The results indicated that there was a positive correlation between weeks after sowing lablab and plant height (R2 = 0.88). Alternate rows showed 35% increase in forage yield (P<0.05) compared to sole maize (control). The 9 days irrigation interval showed 10% increase (P<0.05) in forage yield compared to 3 and 6 days intervals. However, sole maize produced 39% higher (P<0.05) grain yield compared to intercrops. Irrigation interval at 6 days produced 13% higher (P<0.05) maize grain yield compared to 3 and 9 days intervals. The highest (P<0.05) crude protein (CP) content of 21% was observed in sole lablab treatment. Intercropped lablab had the lowest (P<0.05) crude fibre (CF) compared with the control. It was therefore recommended that smallholder farmers in igeria could introduce lablab as a relay crop with irrigated maize for improved livestock performance, income generation and environmental control.Key words: Forage, irrigation, lablab, maize, Nigeri