Simple picrate method for the determination of cyanide in cassava flour

A simple picrate method was used to quantify the cyanide contents of food samples. The cyanide in the food samples reacted with hot 20% HCl solution to produce hydrogen cyanide vapour which reacted with alkaline picrate test strips to form red colour on the test strips. The red coloured complex on the strips was extracted with 50% ethanol solution and the absorbance of the extract was measured at 510nm using a spectrophotometer. The method was reproducible and cyanide as low as 1 microgram could be determined. Cyanide levels of all the cassava varieties tested were higher than the 10ppm WHO safe level. Recovery of cyanide from acyanogenic foods fortified at levels of 5 and 10mg KCN/10g were 98.6% and 99.1% respectively. The picrate method is simple and useful for routine determination of cyanide content of cassava flour.Keywords: Picrate method, Cyanide, Cassava flou

Application of photosynthetic microalgae as efficient pH bio-stabilizers and bio-purifiers in sustainable aquaculture of Clarias gariepinus (African catfish) fry

Chlorella lewinii LC172265 and Scenedesmus dimorphus NIES-93 were grown with BG-11 medium and then transferred to fish seedlings' farm and the effects on changes in the pH, nitrite, total ammonia nitrogen and toxic ammonia were studied. Inoculation of the ponds with C. lewinii, S. dimorphus and the combined culture of C. lewinii and S. dimorphus significantly reduced the rise in the pH of the ponds (p<0.05). With these three cultures, the pond pH increased from 6.3±0.03 to only 6.5±0.2, 6.7±0.6 and 6.4±0.1 respectively within a period of 240 hours, as against control pond's pH which increased from 6.3±0.03 to 9.0±0.1 within the same period. Furthermore, inoculation with S. dimorphus reduced the nitrite concentration in the ponds to zero on the 144th hour and the concentration remained zero throughout the experiment. This was closely followed by the combined culture of C. lewinii and S. dimorphus which reduced the nitrite concentration to zero at 240th hour while C. lewinii was the least in nitrite removal. Toxic ammonia was also zeroed by the combined culture of C. lewinii and S. dimorphus at 144th hour of experiment which was followed by C. lewinii (at 192nd hour). Aquaculture ponds co-cultured with microalgae witnessed a maximum fry death rate of 40% which was much lower than 80% death rate observed in the control ponds. These results show that C. lewinii and S. dimorphus are very efficient in sustaining the quality of aquaculture water, and thus prolonging the length of time water can be used before changing.Keywords: nitrogen removal, ammonia, nitrite, fishery, fish pon

Developing food waste biorefinery: Using optimized inclined thin layer pond to overcome constraints of microalgal biomass production on food waste digestate

Diversion of food waste from landfill through anaerobic digestion is a sustainable form of energy production (biogas) and the waste effluent (digestate) can be utilised as nutrient supply for microalgae cultivation. However, digestate has very high nutrient concentrations and is highly turbid, making it difficult to utilize as a nutrient source with conventional microalgae cultivation systems. Here we compared the efficiencies of a conventional open raceway pond (ORWP) and an improved inclined thin layer photobioreactor (ITLP) for the utilization and treatment of food waste derived digestate by Chlorella sp. The ITLP improved on volumetric and areal productivities by 17 and 3 times over the ORWP, with values of 0.563 and 31.916 g m −2 day −1 respectively. Areal nutrient removal via microalgae biomass were 2359.759 ± 64.75 and 260.815 ± 7.16 mg m −2 day −1 for nitrogen and phosphorous respectively in the ITLP, which are 2.8 times higher than obtained in the ORWP. The ITLP’s superiority stems from its ability to support a much higher average biomass yield of 6.807 g L −1, which was 7 times higher than in the ORWP. Mean irradiance in-situ was higher in the ITLP, irradiance distribution and utilization by the culture in the ITLP was 44% more efficient than in the ORWP. Our results indicate that the ITLP is a far more productive system than conventional raceway ponds. This demonstrates that integration of ITLP microalgae cultivation using digestate has the potential to make digestate management yield net benefit in food waste biorefinery settings

Biological Activities of a Macrocyclic Diterpenoid Isolated from the Roots of Jatropha gossypiifolia

Background: Extracts of Jatropha gossypiifolia L. (Euphorbiaceae) have been used ethnomedicinally for the treatment of various ailments. The present study was to investigate the biological activity of Jatrophone, a macrocyclic diterpenoid isolated from the roots of J. gossypiifolia. Methods: Phytochemical studies followed by chromatographic separation of the methanol root bark extract led to the isolation of a macrocyclic diterpenoid, identified as jatrophone on the basis of NMR and mass spectra data and by comparison with literature. The isolated compound, jatrophone was evaluated for its antiprotozoal activity against Plasmodium falciparum strains [D6 (chloroquine sensitive) and W2 (chloroquine-resistant)], Leishmania donovani and Trypanosoma brucei. The antimicrobial activity was evaluated against type culture of selected fungi and bacteria. Analgesic activity was investigated using the acetic acidinduced writhing and hot plate model in mice. The cytotoxicity was assessed against VERO cell line (monkey kidney fibroblast) using neural red uptake method. Results: Jatrophone showed significant antiplasmodial and antileishmanial activities with IC50 of 0.55, 0.52 and < 0.4 µg/mL for P. falciparum (D6 strain), P. falciparum (W2 strain) and L. donovani respectively. Compound 1 was highly cytotoxic to VERO cell line with IC50 of 0.43 µg/mL. Jatrophone demonstrated significant analgesic effect with a percentage reduction in acetic acid-induced writhes of 54.03% and 66.35% at 5 and 10 mg/kg respectively. No significant antimicrobial activity was observed against the test organisms. Conclusion: The present study has shown that jatrophone possess antimalarial, antileishmanial, and analgesic activitie

Cross-sectional study on COVID-19 prevention and vaccination status of veterinary colleges in Southeast Nigeria

COVID-19 vaccination and compliance with the established prevention protocols are integral to curbing the spread of the COVID-19 virus; however, there is a paucity of information on compliance with these measures among veterinary schools within southeast Nigeria. To fill this gap, we evaluated the vaccination status and individual’s perception of the preventive measures against COVID-19 infections. A cross-sectional study using a self-reported internet-based questionnaire was employed to obtain responses from students and staff of the veterinary colleges in southeast Nigeria. Multivariate binary logistic regression analysis was used to identify significant factors associated with vaccination status and compliance with the COVID-19 prevention protocols by the respondents. A total of 183 individuals participated in the online survey. Although 75% (138/183) of the respondents revealed a willingness to take the COVID-19 vaccine, only 25.1% (46/183) of the respondents had received one or more doses of the COVID-19 vaccine. We observed that male respondents (28 ± 4.4% (95% CI 19–37)) had a higher percentage of vaccinated individuals than female respondents. Furthermore, the academic staff of the veterinary colleges were 39.70 (95% CI 2.50–630.65; ) times more likely to get vaccinated than undergraduate students. The educational status of the respondent greatly contributed to the willingness to get vaccinated, and individuals within the age bracket of 31 to 40 years were 10.2 ± 1.07 (95% CI 1.33–92.25; ) times less likely to comply with the COVID-19 prevention protocols. Although a high proportion of the respondents had a good perception of the COVID-19 prevention protocols, only 25.1% of the members of the veterinary colleges in southeast Nigeria had been vaccinated. Therefore, there is a need to create better awareness channels to improve the vaccination status of members of veterinary colleges in southeast Nigeria

Potentials of microalgae biodiesel production in Nigeria

Bio-energies are renewable, sustainable and environmentally-friendly. Although Nigeria has a lot of various biomass materials, production of bio-fuels in Nigeria is faced with a lot of challenges. It has been argued that large scale production of bio-energies from food crops as replacement or supplements to fossil fuels cannot be realistically achieved because of possible negative effects on food security. There is high potential for largescale production of biodiesel from microalgae in Nigeria. Establishment of biodiesel production industries in Nigeria will have positive effects on socio-economic development of the country. It has been estimated that Nigeria currently needs about 27 thousand barrels of biodiesel per day to be able to replace the entire consumed fossil diesel with B20 blends. There is therefore an urgent need to isolate and develop productive strains that are adapted to non-arable lands in Nigeria, develop appropriate photo bioreactors and culture systems for large scale production of microalgae biodiesel, and develop bioenergy friendly policies and incentives to encourage bio-energy production in Nigeria

Production of Antimicrobial Substances by Lactobacillus plantarum Immobilized in Calcium Alginate Gel Beads

Production of anti-microbial substances by Lactobacillus plantarum, immobilized in calcium alginate gel beads was investigated. The beads were very unstable in De man Rogosa and Sharpe (MRS) medium but the stability of the beads improved by removing potassium and phosphate from the MRS medium. The highest stability of the beads was achieved by addition of calcium chloride to the medium. When 5% calcium chloride was added to the medium, the stability of the beads increased from 24h (when no calcium chloride was added) to 500 h, without adverse effects on the growth and antimicrobial substance production by the immobilized cells. Although the produced antimicrobial substances inhibited the growth of Bacillus cereus, B. subtilis, Listeria monocytogenes, and Escherichia coli, B. subtilis was the most susceptible. Under all the conditions investigated, immobilization of L. plantarum significantly increased the organism’s ability to produce antimicrobial substances. Although suspended cells produced higher antimicrobial substances under anaerobic condition, aerobic condition improved antimicrobial substance production by the immobilized cells. This implies that microaerophilic condition is the best for antimicrobial substance production by L. plantarum.Keywords: Bio-insecticide, anti-microbial substances, Bacillus thuringiensis, endotoxi

Potentials of Exploiting Heterotrophic Metabolism for Biodiesel Oil Production by Microalgae

The current prices of microalgae oils are much higher than oils from higher plants (vegetable oils) mainly due to the high cost of photoautotrophic cultivation of microalgae. However, many strains of microalgae can also grow and produce oil using organic carbons, as the carbon source under dark (heterotrophy) or light conditions (mixotrophy). Lipid productivities of most strains of microalgae are higher in culture systems that incorporate heterotrophic metabolisms (presence of organic carbon source) than under photoautotrophic conditions. This is because for many strains, cell growth rates and final cell concentrations are higher in heterotrophic cultures than in photoautotrophic cultures. Furthermore, in some cases, the oil contents of the cells are also higher in cultures incorporating heterotrophic metabolisms. It has also been reported for some strains that the quality of oil produced in the presence of organic carbon sources are more suitable for biodiesel oil production than those produced under photoautotrophic conditions. Thus, heterotrophy can be used to reduce the cost of biodiesel oil production, but the effectiveness of the various organic carbons in supporting cell growth and oil accumulation depends on the strain and other culture conditions. Use of wastewaters for cultivation of microalgae can further substantially reduce the cost of production (since they contain carbon, nitrogen, and other nutrients) and also reduce the requirement for freshwater. Generally, many factors such as nitrogen limitation, phosphate limitation, silicon limitation, control of pH, and low temperature can be used to increase oil accumulation, although their effectiveness depends on the strain and other culture conditions

Effects of light intensity and photoperiod on growth, lipid accumulation and fatty acid composition of Desmodesmus subspicatus LC172266 under photoautotrophic cultivation

Microalgae oil accumulation in their natural growing states hardly reaches the quantities needed to replace fossil-derived diesel. Therefore, for algae to be used as biofuel feedstock, their growths are manipulated with the aim of achieving high cell density and high lipid accumulation. Two major factors affecting microalgal biomass and lipid productivity are light intensity and photoperiod. In the present study, Desmodesmus subspicatus was grown photoautotrophically under varying light intensities and photoperiods with a view to assessing the growth, lipid accumulation potential and fatty acid composition. Whereas the optimal light intensity for biomass production of the microalga was 5000 lx, that for lipid productivity was 3500 lx. At 5000 lx and 18: 6 h light/dark cycle, biomass yield, lipid content and lipid productivity were highest, at values of 1.92 ± 0.03 g/L, 53% and 118.80 ± 2.04 mgL-1day -1 respectively. The major fatty acid of the alga was oleic acid irrespective of light changes. The quantities of lipid accumulated and the properties of the fatty acid methyl esters showed that Desmodesmus subspicatus LC172266 is an ideal feedstock for biodiesel production

Growth comparison of microalgae in tubular photobioreactor and open pond for treating anaerobic digestion piggery effluent

The overwhelming interest in the use of microalgae to handle associated nutrient surge from anaerobic digestion technologies for the treatment of wastewater, is driven by the need for efficient nutrient recovery, greenhouse gas mitigation, wastewater treatment and biomass reuse. Here, the feasibility of growth and ammonium nitrogen removal rate of semi-continuous mixed microalgae culture in paddle wheel-driven raceway pond and helical tubular closed photobioreactor (Biocoil) for treating sand-filtered, undiluted anaerobic digestion piggery effluent (ADPE) was compared under outdoor climatic conditions between June and September 2015 austral winter season. Two Biocoils, (airlift and submersible centrifugal pump driven) were tested. Despite several attempts in using airlift-driven Biocoil (e.g. modification of the sparger design), no net microalgae growth was observed due to intense foaming and loss of culture. Initial ammonium nitrogen concentration in the Biocoil and pond was 893.03 ± 17.0 mg NH4 +-N L-1. Overall, similar average ammonium nitrogen removal rate in Biocoil (24.6 ± 7.18 mg NH4 +-N L-1 day-1) and raceway pond (25.9 ± 8.6 mg NH4 +-N L-1 day-1) was achieved. The average volumetric biomass productivity of microalgae grown in the Biocoil (25.03 ± 0.24 mg AFDW L-1 day-1) was 2.1 times higher than in raceway pond. While no significant differences were detected between the cultivation systems, the overall carbohydrate, lipid and protein contents of the consortium averaged 29.17 ± 3.22, 32.79 ± 3.26 and 23.29 ± 2.15% AFDW respectively, revealing its suitability as animal feed or potential biofuel feedstock. The consortium could be maintained in semi-continuous culture for more than three months without changes in the algal composition. Results indicated that microalgae consortium is suitable for simultaneous nutrient removal and biomass production from piggery effluent