In Nigeria and many other developing countries of the world, the incidence of mycotoxin- contamination of foods and food products has attracted attention and stirred a lot of concern for food safety. This work aims at detection of aflatoxigenic and ochratoxigenic synthetic genes from fungal isolates of palm oil as a veritable means for the evaluation of foods for possible mycotoxin contamination.  In this study, fungal isolates from palm oil samples collected from the five states of South-east geopolitical zone in Nigeria were screened for  aflatoxin and ochratoxin biosynthetic genes using Multiplex Polymerase Chain Reaction (mPCR). The assay relied on three sets of primers that amplify aflatoxgenic Aspergillus, ochratoxigenic Aspergillus and Penicillium species under optimized PCR conditions. Optimum multiplex PCR assay was standardized for simultaneous detection of toxigenic Aspergillus and ochratoxin producing Penicillium species targeting AflR, AflS and pks genes involved in aflatoxin and ochratoxin metabolic pathways respectively. AflR primer pair gave specific amplification for aflatoxigenic A. flavus but did not give amplification for A. niger and P. chrysogenum. While AflS and pks gave amplification for only aflatoxigenic and ochratoxigenic A. niger and P. chrysogenum. In the evaluation and monitoring of mycotoxin-producing fungi during the processing of food and feed commodities, Multiplex PCR approach could be a veritable tool to supplement the conventional analytical techniques.

Aims: To optimize effects of selected process parameters affecting yield of green synthesized silver nanoparticles and their antibacterial activity. Study Design: Study was designed with 3 factors Box Behnken Design (Minitab 17) and Response optimizer (Minitab 17) was used to determine optimum values of the factors. Place and Duration of Study: Department of Microbiology, Federal University of Technology, Owerri, Nigeria, from March to November, 2020. Methodology: After extraction by boiling, qualitative phytochemical analysis of leaves’ extracts of Ipeoma batatas, Commelina africana and Manihot esculenta was carried out. Following synthesis of silver nanoparticles as prescribed by Box Behnken design, yield of AgNPs was optimized with Response optimizer (Minitab 17). Then antibacterial activity of resulting AgNPs was tested against isolates of P. aeruginosa and E. coli. Results: Extracts contained alkaloids, tannins, proteins and amino acids, flavonoids and phenolic compounds, but no sterols and cardiac glycosides. Optimum pH, temperature and time obtained with Response Optimizer resulted in 62.6%, 55.8% and 54.9% increase in yield of AgNPs, with leaf extracts of C. africana, M. esculenta and I. batatas respectively, compared to un-optimized conditions. Absorbance for resulting AgNPs peaked between 380 to 400 nm. Zones of inhibition (mm) of P. aeruginosa with AgNPs synthesized using extracts of C. africana, I. batatas and M. esculenta were 10, 10 and 9 respectively, under un-optimized condition, and 12, 10 and 8 respectively, for optimized conditions. Against E. coli, they were 11, 11 and 12 for AgNPs synthesized with extracts of C. africana, I. batatas and M. esculenta respectively, under un-optimized condition, and 13, 9 and 11 respectively, for optimized conditions. Conclusion: Leaf extracts of C. africana, I. batatas and M. esculenta can be used in synthesizing AgNPs, with marked antibacterial activities. Box Behnken design is useful for optimization of effects of process parameters.

The role of microbes in the corrosion of metals is due to the chemical activities (metabolism) associated with the microbial growth and reproduction. A lot of researches have shown that enormous loss of resources and even lives has been experienced in many countries of the world due to corrosion. There is therefore need to device a means of combating this menace so as to save different countries of the world including Nigeria the cost encured due to corrosion. This research has helped to determine the role of bacteria in the corrosion of high carbon steel under aerobic and anaerobic conditions was investigated using sulphate reducing bacteria and other aerobes. A sample of high carbon steel grade of chemical composition: 96% iron (Fe), 1.08% carbon (C), 0.349% silicon (Si), 0.841% manganese (Mn), 0.005% phosphorus (P) and 0.005% sulphur (S), was obtained in the form of steel plate. Eighteen (18) samples of the high carbon steel were prepared. Standard microbiological methods were used to isolate aerobic and anaerobic bacteria isolates. The microbes isolated from the soil included; aerobes (Bacillus species, Pseudomonas species) and anaerobes (Desulfovibrio species, Thiobacillus species).The role of bacteria in the corrosion of high carbon steel was estimated using the weight loss technique and the electrochemical potential measurement technique. Eighteen samples of a high carbon steel of known compositions were exposed to sulphate reducing bacteria under different environments (aerobic, anaerobic and control). The physical and chemical changes were examined and monitored on weekly basis for six weeks. It was observed that the coupons immersed in the media with sulphate reducing bacterium underwent fast activation and numerous corrosion sites were formed on the surfaces. The average corrosion rate for six weeks (42 days) period of time as determined by the weight loss method and electrochemical testing were How to cite this paper: Nwokorie, R.C., 228Materials Sciences and Applications found to be 0.0004595 mm/year, −0.712 mV in aerobic environment, 0.0005646 mm/year, −0728 mV in anaerobic environment and 0.0004458 mm/year, −0702 mV in the control or reference environment (distilled water environment). High carbon steel was found to corrode more only in the anaerobic environment. In view of this, high carbon steels were found to be relatively more corrosion resistant than mild and medium carbon steels and may be suitable for application in industries such as the petrochemical industry. Therefore, treating the environment with chlorine but with caution as solutions of chlorine gas in water is corrosive to steels while the use of bactericides or biocides to arrest the action of microbes is important.

This study aimed to investigate anaerobic co-digestion of palm oil mill effluent (POME) with cassava peels (CP) and cabbage waste (CW) for biomethane production. The anaerobic digestion (AD) in 10L capacity bioreactors loaded separately with three different ratios (3L/ 520g, 3L/ 600g and 3L/ 680g) of POME/CP, POME/CW and POME only (control) was operated under ambient temperature (25 - 36⁰C) and pH range of 6.5 - 8.5 for 45 days. Standard methods were adopted in the characterization of the bioreactor feeds and microbiological study. The biomethane content of the biogas was determined using Gas Chromatography (GC). The results showed the presence of Escherichia coli, Staphylococcus, Pseudomonas sp, Bacillus sp Salmonella sp among others. Fungal isolates identified include Saccharomyces, Aspergillus, Rhizopus, Penicillum, and Geotrichum species. The mean cumulative biogas yield recorded in bioreactors charged with POME/ CP 520g, POME/ CP 600g, POME/ CP 680g and POME/CW 520g, POME/CW 600g, POME/CW 680g were 7.08, 5.18, 9.06, 9.13, 9.28 and 8.33 dm3, respectively, whereas POME alone (control) was 4.64 dm3. The best performance in biogas yield was exhibited by POME/CW 600g (9.28dm3), and the highest percentage biomethane content (68.80%). Analysis of variance (ANOVA) revealed a significant difference (P ≤ 0.05) in biogas yield in all the treatments compared to control (POME alone) except in POME/CP 3L: 520g and POME/CP 3L: 600g. The results have shown that biogas production and biomethane content could be efficiently improved via co-digestion process, depending on the substrates used as feedstock.

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