Annual Research & Review in Biology

Metals can be leached either directly (physical contact between microorganisms and solid material) or indirectly. The removal of metals from these industrial wastes brings out detoxification of the residues and thus improves the quality of the environment. The waste foundry sand was analyzed for the presence of toxic metals, as the plant uptakes these toxic metals through their food chain which in turn may be harmful to the human beings. In this study Hibiscus was grown on sand blends containing 50% of waste foundry sand (WFS) to assess the availability of Sio₂, Al, Ca, Mg, Pb, Cu and Zn. The chemical properties of treated and untreated waste foundry sand were observed. The analysis shows the level of untreated WFS Fe (76.36%), Ca (43.65%) and K (37.49%). Actinomyces sp. was isolated and identified from WFS and was used to bioleach the sand (treated) and was observed to reduce the level of metals present in WFS [Fe (26.54%), Ca (27.67%) and K(5.84%)] and untreated foundry sand had metal levels of [Fe(49.82%), Ca (15.98%) and K(31.65%)]. The treated and untreated sand was later used for growing Hibiscus plant sapling under controlled conditions and was analyzed for the traces of metals absorbed by the plant. The presence of metals was calculated by Atomic Emission Spectroscopy technique that can determine the concentration of trace to major elements. Our observations provide a supportive document on bioleaching of WFS by Actinomyces sp. was adequate in the growth of ornamental plant Hibiscus rosa-sinensis.

Aim: To assess natural electrogenicity and bioelectricity generation potentials of microbial isolates from water sites in Nigeria

Study Design: Sampling of various water sites and microbial isolation for subsequent electrogenic characterization of isolates and bioelectricity generation

Place and Duration of Study: Department of Microbiology, University of Ibadan, Ibadan, Oyo state,

Nigeria between January 2014 to June 2015.

Methodology: Various water sites in Nigeria were assessed, and samples collected. Isolation and identification of bacteria and yeasts were carried out using standard techniques. Electrogenic screening of pure culture using Open Circuit Voltage (OCV) measurements in biolelectrochemical reactors and Cyclic Voltammetry were carried out. Bioelectricity generation measurements using multimeters and calculations of Voltage, Current, Power and Coulombic efficiency in Open and Closed circuit systems were calculated.

Results: A total of 362 microorganisms (254 bacteria; 108 yeasts) were isolated and screened for electrogenicity. Samples from a River Benue site in Yola, Nigeria harboured the highest number of electrogenic isolates among all sites assessed. Sixty-five microorganisms elicited electrogenicity out of which 47 were bacteria and 18 were yeasts. Based on their electrogenic potentials, 7 of the most efficient isolates with electrogenic voltages >500 mV were further selected, and molecularly identified by 16S rRNA and ITS region gene analyses as Pseudomonas aeruginosa A4 (KX397030), Pseudomonas aeruginosa B3 (KX397029), Enterobacter aerogenes 102 (KX397032), Pseudomonas sp. B1 (KX397031), Pseudomonas aeruginosa 104, Bacillus cereus 101 (KX397028) and Pichia kudriavzevii 103 (KX397033). Cyclic voltammetry carried out on the isolates confirmed their electroactivity in comparison with a non-electrogenic Escherichia coli ATCC 25922 strain. Bioelectricity generation experiments showed that P. aeruginosa A4 was the most electrogenic strain, eliciting the highest current of 86.37 ± 14.52 mA/m². The least current was observed for the Pichia kudriavzevii 103 strain (19.22 ± 9.02 mA/m²).

Conclusion: All isolates proved to be good electrogens and efficient candidates for optimising bioelectricity production.

In the present study, to investigate genetic diversity and phylogenetic relationships among honey bee populations of Iraq ISSR markers were used. Sampling was carried out during summer 2017 from 5 cities of Iraq (Dahuk, Arbil, Sulaymaniyah, Kirkuk, and Kafri). Total DNA was extracted from the head and thorax sections of each worker honey bee, using salting out method with minor modifications. PCR amplification of genomic DNA was performed using 10 ISSR marker primers (A1, A2, A3, A4, A5, A6, A7, A8, A9 and A10). The primers yielded 50 polymorphic bands and number of bands were variable from 8-12 (average 9.62), and percentage of polymorphic loci was 73.6. The estimated genetic diversity for the populations ranged from 0.39 in Kafri population to 0.47 in Arbil population, and total genetic diversity among loci was calculated as 0.47 while average within population genetic diversity was 0.44. GST value was 0.085. The Phylogenetic tree showed two main clusters; the first one comprised of three populations (Dahuk, Arbil, and Sulaymaniyah), and the second one included two communities (Kirkuk and Kafri). Heterozygosity values, Shannon index and the number of alleles of honey bee populations were minimal that could be caused by low definite geographic structure of honey bee populations. This research provided new information regarding genetic diversity in selected local honeybee in Kurdistan region of Iraq and will be useful for selection, future local biodiversity conservation and controlled breeding programs.

The study was conducted to determine fungal communities associated to strawberry plant roots, densities of nematodes in fumigated soil and physico-chemical properties of soil in three commercial strawberry plots (Dlalha, Ouled Aguile and Gnafda) located in Gharb region and visited three times during 2013-2014 season. Under a slight variation of soil temperature and humidity with specific physico-chemical characteristics, a high infestation level of soil by nematodes was marked in the studied farms over the periods of sampling. The lowest number was observed in the first visit attaining 1000 units/g of soil, increased to 5000 units/g of soil in the second sampling period at one site and in the last visit, a significant decrease trend occurs for the big plot which the number of nematodes was reduced to 1500 units/g of soil. The analysis of fungal communities colonizing roots of strawberry plants showed the presence of 13 fungal species. Rhizoctonia solani presented a higher frequencies of isolation from roots of Festival variety reaching respectively 36% and 26.72% in the first and the second visits of Dlalha farms compared to those recorded in the second visit of Ouled Aguile (18%) and Gnafda (13.6%) farms. The Fusarium genus was represented by F. solani, Fusarium sp.1 and Fusarium sp.2 detected at frequencies not exceeding 7.08%. Those of C. gloeosporioides reached 12%, Phytophthora sp. (15.8%). In addition, the appearance of A. alternata, C. herbarum, Aspergillus sp., Circinella sp., Ulocladium sp. and Trichoderma asperellum was more frequent during the three sampling periods.

Sodium dodecyl sulfate, (SDS) is an anionic surfactant that widely utilized in industry and households. Which represent toxic effects to the health and aquatic organisms. The bacterial strains Pseudomonas aeruginosa and Pseudomonas otitidis were isolated from the water samples from waste disposal sites (Taif Governate, Kingdom of Saudi Arabia). So, in the present study, we have made an attempt to improve the biodegradation of SDS by Pseudomonas aeruginosa and Pseudomonas otitidis by different methods such as mutation (Physically and chemically), physically by exposure of bacterial strains to ultraviolet radiation (UV) and chemically by using chemicals such as ethidium bromide (EtBr), also biodegradation rate of SDS can be increased by immobilization technique. The bacterial strains were immobilized in alginate beads, and its SDS degradation efficiency was observed to increase many fold than free strains.