The aerobic dechlorination activities of two bacterial species isolated from a refuse dumpsite in Nigeria

Two bacterial species isolated using enrichment culture techniquesfrom the topsoil of a main refuse dumpsite in Nigeria were assessed for their dehalogenation potentials. The bacterial isolates were identified asbelo nging to the Bacillus and Pseudomonas genera. Axenic culturesof the isolates utilized monochloroacetic acid (MCA), trichloroacetic acid (TCA), trichloromethane (CHCl3) and tetrachloromethane (CCl4) as the sole source of carbon for growth up to a final substrate concentration of 0.1% (w/v). The mean generation timesof the isolatesin all the growth media ranged significantly (P < 0.05) from 2.41 to 10.04 h and were generally higher than that observed in glucose medium (1.46—1.51 h). The numbers of the chloride atoms in the different organochlorides were negatively correlated with the ability of the organisms to degrade the compounds. Dehalogenase specific activities of the cell-mediated culturesranged from 0.1 to 0.96 μg ml-1 chloride release (mg protein)-1 h-1 and were significantly (P < 0.05) higher than that of the cell-free extract [0.09—0.8 μg ml-1 chloride release (mg protein)-1 h-1]. The optimal pH of the dehalogenase activity was found to be 8.0, and the optimal temperature was between 30 and 35°C

Effects of fermentation temperature on the composition of beer volatile compounds, organoleptic quality and spent yeast density

Production of good quality beer is dependent largely on the fermentation temperature and yeast strains employed during the brewing process, among others. In this study, effects of fermentation temperatures and yeast strain type on beer quality and spent yeast density produced after wort fermentation by two commercial yeast strains were investigated. Beer samples were assessed for colour, clarity and foam head stability using standard methods, whilst the compositions and concentration of Beer Volatile Compounds (BVCs) produced were assessed using GC-MS. The spent yeast density, measured as dry cell weight, ranged between 1.84 - 3.157 mg/ml for both yeast strains with the highest yield obtained at room temperature fermentation. A peak viable population of 2.56 x 107 cfu/ml was obtained for strain A, also during fermentation at room temperature. The foam head of the beers produced at 22.5\ubaC was most stable, with foam head ratings of 2.66 and 2.50 for yeast strain A and B, respectively. However, there was no significant (p = 0.242) difference in colour intensity between the beers produced at the different fermentation temperatures. Eight different BVCs were detected in all beer samples and were found to affect the organoleptic properties of the beer produced. Further optimizations are required to determine the effects of other parameters on beer quality

The Utilization of Building Information Modeling In Nigerian Construction Industry: Challenges and Prospects

The aim of this research is to appraise the challenges and prospects in the use of Building Information Modeling (BIM) in the construction industry in Nigeria. It analyzed the uses of BIM in the construction industry, determined the stakeholders perception of the benefits, risk and benchmarks in the adoption of BIM in construction practice and process. It examined the extent of its interoperability in bringing together the different participants and processes of construction works for efficiency and effective construction management and timely project delivery. It compared the findings with the same studies carried out and/or currently being carried out in many parts of the world. Primary data were collected through structured questionnaires. The questionnaires were distributed and collected through personal contacts, letters, online groups and e-mails. Direct observation and interviews were made with professionals in the construction industry The secondary data were obtained from the exploration of various relevant literature and previous researches that have been done in relevant areas. A purposive and modified BIM measurement survey was used for this research work to gather the opinion and views of various construction professionals and clients A total of One Hundred and Fifty (150) questionnaires were distributed based on the sample population. One Hundred and Thirty-two (132) questionnaires were retrieved and used to obtain the required information for data. Tools used the purpose of this research include mean score, percentile and inferential method of statistical analysis. The statistical package for social science (SPSS) was basically used to create the frequency tables and the charts. The study showed that the application of BIM is economical and easy leading to improvement, enhanced technical and general management of construction projects which can lead to total control of cost estimates, prompt delivery of projects and quality are the most important key performance indicators in construction

Microbial proteases: A next generation green catalyst for industrial, environmental and biomedical sustainability

Proteases are among the most important classes of hydrolytic enzymes and occupy a key position due to their applicability in both physiological and commercial fields. They are essential constituents of all forms of life, including plants, animals, and microorganisms. However, microorganisms represent an attractive source for protease secretion due to their high productivity in a relatively short time and limited space requirements for cultivation, amongst others. Microbial proteases are produced by submerged or solid-state fermentation process during post-exponential or stationary growth phase. The production of these biocatalysts by microbes is influenced by nutritional and physicochemical parameters. Downstream recovery of high-value enzyme products from culture supernatant using suitable techniques is imperative prior to further use of the biocatalysts. Immobilization of these enzymes in appropriate matrices permits reusability, reclamation, enhanced stability and cost-effectiveness of the biocatalysts. The catalytic properties of microbial proteases help in the discovery of enzymes with high activity and stability, over extreme temperatures and pH for utilization in large-scale bioprocesses. This review provides insights into microbial proteases taking cognizance of the bioprocess parameters influencing microbial proteases production coupled with methods employed for protease purification as well as the immobilization and biochemical properties of the biocatalysts for potential biotechnological applications

Factors Militating Against Prompt Delivery of Construction Projects in Lagos Megacity, Nigeria: Contractors’ Perspective

Delay is a common issue faced in the construction industry all over the world especially in developing countries. The aim of this study is to evaluate factors causing delays and their effects on construction projects in Lagos Mega City, Nigeria from the contractors’ perspective. It is predicated on the incessant delay experienced by contractors on construction projects. Purposive sampling method was adopted for the study;. Quantitative data was obtained by administration of One hundred (100) structured questionnaires distributed to contractors of construction project sites in Lagos State and Qualitative data was obtained from interview of key management personnel of the companies and journals. Ranking analysis of the 33 major causes of delays identified through literature review using Relative Importance Index (RII) showed that cash flow problems during construction (RII=4.81), clients’ financial difficulties (RII=4.47) and poor procurement (RII=4.40) were the most importantt causes of delays in construction project sites in Lagos State, Cost overrun (RII=4.92), late payment (RII=4.59) and project extension (RII=4.45) were predominant effects of delay in construction project. Hypotheses testing on relationship between shortage of skilled labour, improper equipment during construction and delay in construction project using One-Way ANOVA showed positive correlation. For improved efficiency and effective project delivery in the industry, proper payment from client (RII=4.78), competent project managers (RII=4.64), the use o

Antibiotic Producing Potentials of Three Freshwater Actinomycetes Isolated from the Eastern Cape Province of South Africa

Crude extracts of three actinomycetes species belonging to Saccharopolyspora (TR 046 and TR 039) and Actinosynnema (TR 024) genera were screened for antibacterial activities against a panel of several bacterial strains. The extracts showed antibacterial activities against both gram-negative and gram-positive test bacteria with inhibition zones ranging from 8 to 28 mm (TR 046); 8 to15 mm (TR 039); and 10 to 13 mm (TR 024). The minimum inhibitory concentrations ranged from 0.078 to 10 mg/mL (TR 046); 5 to >10 mg/mL (TR 039); and 1.25 to 5 mg/mL (TR 024). Time-kill studies revealed that crude extract of TR 046 showed strong bactericidal activity against Bacillus pumilus (ATCC14884), reducing the bacterial load by 104 cfu/mL and 102 cfu/mL at 4× MIC and 2× MIC, respectively, after 6 h of exposure. Similarly, against Proteus vulgaris (CSIR 0030), crude extract of TR 046 achieved a 0.9log10 and 0.13log10 cfu/mL reduction at 5 mg/mL (4× MIC) and 1.25 mg/mL (2× MIC) after 12 h of exposure. The extract was however weakly bactericidal against two environmental bacterial strains (Klebsiella pneumoniae and Staphylococcus epidermidis); and against Pseudomonas aeruginosa (ATCC 19582): the extract showed bacteriostatic activities at all concentrations tested. These freshwater actinomycetes appear to have immense potential as a source of new antibacterial compound(s)

Treated Wastewater Effluent as a Source of Microbial Pollution of Surface Water Resources

Since 1990, more than 1.8 billion people have gained access to potable water and improved sanitation worldwide. Whilst this represents a vital step towards improving global health and well-being, accelerated population growth coupled with rapid urbanization has further strained existing water supplies. Whilst South Africa aims at spending 0.5% of its GDP on improving sanitation, additional factors such as hydrological variability and growing agricultural needs have further increased dependence on this finite resource. Increasing pressure on existing wastewater treatment plants has led to the discharge of inadequately treated effluent, reinforcing the need to improve and adopt more stringent methods for monitoring discharged effluent and surrounding water sources. This review provides an overview of the relative efficiencies of the different steps involved in wastewater treatment as well as the commonly detected microbial indicators with their associated health implications. In addition, it highlights the need to enforce more stringent measures to ensure compliance of treated effluent quality to the existing guidelines

Treated Wastewater Effluent as a Source of Microbial Pollution of Surface Water Resources

Abstract: Since 1990, more than 1.8 billion people have gained access to potable water and improved sanitation worldwide. Whilst this represents a vital step towards improving global health and well-being, accelerated population growth coupled with rapid urbanization has further strained existing water supplies. Whilst South Africa aims at spending 0.5% of its GDP on improving sanitation, additional factors such as hydrological variability and growing agricultural needs have further increased dependence on this finite resource. Increasing pressure on existing wastewater treatment plants has led to the discharge of inadequately treated effluent, reinforcing the need to improve and adopt more stringent methods for monitoring discharged effluent and surrounding water sources. This review provides an overview of the relative efficiencies of the different steps involved in wastewater treatment as well as the commonly detected microbial indicators with their associated health implications. In addition, it highlights the need to enforce more stringent measures to ensure compliance of treated effluent quality to the existing guidelines

Prevalence of Antimicrobial Resistant and Virulent Salmonella spp. in Treated Effluent and Receiving Aquatic Milieu of Wastewater Treatment Plants in Durban, South Africa

In this study, we evaluated the impact of treated wastewater effluent from two wastewater treatment plants on the physicochemical parameters and Salmonella spp. load of receiving rivers. Presumptive Salmonella spp. were obtained at all sampled points including the discharge points, with counts ranging from 0 to 4.14 log cfu/mL at both plants. Turbidity, chemical and biological oxygen demand were found to be high and mostly above the required limit for treated wastewater discharge. However, recorded nitrate and phosphate values were very low. Of the 200 confirmed Salmonella spp. isolates recovered from the treated effluent and receiving surface waters, 93% harbored the spiC gene, 84% harbored the misL gene, and 87.5% harbored the orfL gene while 87% harbored the pipD gene. The antibiotic resistance profile revealed that the isolates were resistant to sulfamethoxazole, nalidixic acid and streptomycin, but susceptible to quinolones and third generation β-lactams. These results indicate that in South Africa treated effluents are still a major source of contamination of rivers with pathogens such as Salmonella. Appropriate steps by the regulatory authorities and workers at the treatment plants are needed to enforce stipulated guidelines in order to prevent pollution of surface water resources due to the discharge of poorly treated effluents

Optimization of culture conditions for enhanced lipase production by an indigenous Bacillus aryabhattai SE3-PB using response surface methodology

Lipases are enzymes that hydrolyze fats into fatty acids and glycerol at the water–lipid interface and are also involved in a variety of bioconversion reactions in non-aqueous and micro-aqueous environments. In this study, we optimized the culture conditions for extracellular lipase production by an indigenous lipase-producing bacterial strain isolated from lipid-rich wastewater, using response surface methodology. The studied isolate was identified as Bacillus aryabhattai SE3-PB by polymerase chain reaction and analysis of 16S rDNA. Sunflower oil was found to induce maximum lipase production. Face centered central composite design revealed that temperature (40 °C), pH (7.6), inoculum volume (2.8%, v/v), agitation (193 rpm) and inducer oil concentration (2%, v/v) significantly influenced lipase production at the respective optimum conditions. The coincidence of observed lipase production (264.02 ± 1.94 U/mL) with predicted lipase yield (265.82 U/mL) coupled with a high correlation coefficient (R2 = 0.9919, P < 0.01) confirmed the validity of the model. A 7.2-fold increase in lipase production was obtained in the optimized medium compared to the basal medium. These findings provide the first report on lipase production and optimization by B. aryabhattai SE3-PB and suggest a rational choice of optimum processing conditions for commercial lipase production by B. aryabhattai SE3-PB