In-vessel composting, a contribution to sustainable solid waste management, was conducted on source-separated waste materials generated in Abeokuta city, south-west Nigeria. Feedstock (household, agricultural and municipal waste) and the resultant composts were chemically characterized using standard procedures. Identification and changes in the microbial population during composting, the effects of composting on waste volume reduction (WVR) and elemental composition of composts were evaluated. Product performance on plant growth and metal uptake were then assessed using African spinach (Amaranthus hybridus) in a screen house for 8 weeks. Metals were determined in acid digest using atomic absorption spectrometry. Compost yields and WVR ranged from 35.28 to 48.68% and 51.66 to 64.72%, respectively. Compost heavy metal (Cu, Cr, Zn, Ni, Cd and Pb) concentrations (mg kg( -1)), ranging from 0.67-0.82; 0.13-7.5; 0.001-0.22; 1.67-18.33; 6.50-17.67; and 0.83-6.00 for Cu, Pb, Cd, Ni, Cr and Zn, respectively, were within limits for class A+ composts. The effect of composting varied with element type and significantly (p < 0.05) reduced microbial population by 44.44 to 88.46%. Plant height, leaf number and biomass yield gave positive correlations (r = 0.950 to 0.977; 0.978 to 0.989 and 0.99, respectively; p < 0.05) with applied compost rate. Low-metal composts were produced but the presence of Cd and Pb in plant tissues calls for further research on the long-term effect of products on plant metal uptake in amended soils. The study is a contribution to the data bank of composting as a low technology waste management option in the developing countries.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major threat to public health. This study investigated the occurrence of MRSA in humans, chickens, chicken meat and environmental samples within poultry farms and live bird markets in southwestern Nigeria. Methods: MRSA were isolated using selective culture and tested for antimicrobial susceptibility by broth microdilution. Selected isolates were characterized by whole genome sequencing (WGS). From WGS data, spa, dru, multilocus sequence typing (MLST) and SCCmec types, but also virulence and antimicrobial resistance genes, were identified. Results: Fifty-six MRSA isolates were detected in 734 samples. They showed resistance to β-lactams (100%), tetracycline (60.7%), ciprofloxacin (33.9%), erythromycin (28.6%), gentamicin (32.1%), and trimethoprim/sulfamethoxazole (10.7%). All 30 isolates investigated by WGS carried mecA, dfrG, and tet(38) genes. Other resistance genes detected were blaZ (83.3%), fosB (73.3%), tet(K) (60.0%), aacA-aphD (36.6%), aphA3 (33.3%), msr(A) (30.0%), mph(C) (30.0%), dfrS1 (3.3%), and sat4 (3.3%). Seven spa types (t091, t314, t657, t1476, t2331, t4690 and t12236), four known (dt9aw, dt10ao, dt10cj, and dt11a) and two novel (dt10dr and dt11dw) dru types, as well as five sequence types (ST8, ST121, ST152, ST772 and ST789) were found among the MRSA isolates. All ST121 isolates carried an SCCmec type IV cassette and were not dru-typeable. ST152 and ST121 were found only in specific sample categories within defined locations, while ST8 and ST772 were distributed across most sample categories and locations. Three SCCmec types, IVa, V and Vc, were identified. All MRSA isolates possessed virulence genes including aur, clpP, coa, fnbA, esaA, hly, hla, ica, isdA, srtB, sspA, and vWbp, among others. The toxic shock syndrome toxin gene (tst) was not detected in any isolate, whereas the Pantone–Valentine leukocidin genes lukF-PV/lukS-PV were present in all ST121, all ST772, and all but one ST152 isolates. Conclusion: The results of this study (i) showed that chicken meat is contaminated by MRSA and (ii) suggested that live bird markets may serve as focal points for the dissemination of MRSA within the community.

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Biochar is a stable solid material made from biomass via pyrolysis and can endure in soil for thousands of years. The present study aimed to evaluate the potential of rhizospheric microorganisms in rice-husk and poultry waste biochar-amended soil for biosurfactant production. Rhizospheric microorganisms in biochar-amended soil were isolated and screened for biosurfactant production using different screening methods. Potential rhizospheric bacteria was used to produce biosurfactant using different recovery techniques and its hydrocarbon degrading efficiency was determined. A total of 41 rhizospheric bacteria were recovered from biochar-amended soil. Pseudomonas and Bacillus spp were the dominant isolates. Pseudomonas putida showed best biosurfactant potential isolates from the different screening results and was used to produce biosurfactant. Chloroform-methanol showed good recovery solvent for biosurfactant extraction. Chloroform/methanol (2:1) gave the highest quantity (3.15 ± 0.26) g/L of biosurfactant while ethyl acetate produced the least yield of biosurfactant (1.13 ± 0.82) g/L. Pseudomonas putida also showed the potential to degrade hydrocarbon over a period of 10 days. The results obtained revealed that potential isolates for biosurfactant production and efficient hydrocarbon degraders could be recovered from rice-husk and poultry waste biochar-amended soil.

The use of plant growth promoting rhizobacteria (PGPR) as biofertilizer is a relatively safer, environment friendly and cost effective. This work was designed to assess plant growth promoting abilities of rhizobacteria and evaluate their effect on germination and growth of maize. The bacteria were isolated and screened for plant growth promoting abilities using Pikovskaya agar, Aleksandrov agar and Jensen media. Twelve isolates that showed multiple attributes were further screened for indole acetic acid (IAA) and gibberellic acid (GA) production; best five isolates were selected for further studies. The results of IAA and GA production showed a considerable amount of IAA and GA produced by the isolates which ranged between 9–94 and 21–97 mg l–1, respectively. The selected isolates identified as Bacillusmojavensis, Pseudomonas aeruginosa, Alcaligenes faecalis, Pseudomonas syringae and Bacillus cereus showed a significant difference(P≤0.05) in the amount of potassium(K) and phosphorus(P) solubilized at different source of K (KCl and mica powder) and P (Ca2PO4 and rock phosphate). The isolates also recorded significant level of nitrogen fixing ability with Alcaligenes faecalis strain P156 fixing the highest amount of nitrogen (11.4 mg N fixed per l) and least by Bacillus mojavensis strain NBSL51 (6.3 mg N fixed per l).The results of plant inoculation test showed that Bacillus cereus strain 20UPMNR significantly enhanced the root and shoot dry weight. All the selected isolates enhanced shoot and root length except Bacillus mojavensis which produced less effect on root length when compared to the control. These results have provided vital information for the development of a bio fertilizer for maize.