Heavy metal pollution generally occurs due to socio-economic, industrial, and anthropogenic activities, which may cause an environmentally hazardous and serious severe threat to the survival of the organisms (genotoxic, carcinogenic, and clastogenic effects on it). Many physical and chemical remediation approaches have been proposed to deal with this pollution, but these are very time-consuming and costly. While bioremediation stands out as an inexpensive and efficient approach, the use of bacteria is thought to be a potential and productive organism to prevent this pollution. This review has evaluated the bacterial potential to clean up heavy metals from the environment and elucidated the mechanisms responsible for bioremediation.

The roles of protein in bodybuilding and the regulation of biological processes are important in sustaining life. A large amount of protein is required by both humans and animals and this cannot be supplied by only conventional sources. This is because of the rapid increase in world population. The present sources of protein will not meet global protein demand in years to come. Scientists explore the production of single-cell protein (SCP), as an alternative source of protein, through the utilization of wastes and low-value materials. SCP can supply high-quality protein containing both essential and non-essential amino acids that can be utilized by humans and animals. Protein from microbial biomass is cheaper than animal proteins because the substrates used in the production are generally cheaper and more readily available. Moreover, the production process does not require arable land and the entire process can be completed within a short time. This article reviewed the process of SCP production. Different raw materials used in the production and variations in growth media preparation methods were discussed. Various sources of fermentation microorganisms and their potential substrate were reviewed. Growth media enrichment using different carbon, nitrogen, and mineral sources was also discussed.

This study investigated the prevalence and concentration of antibiotic residues in twenty brands of milk. Determination and quantification of antibiotic residues was done using High Performance Liquid Chromatography. Aerobic plate count was carried out and the associated bacteria isolated. Identification of bacteria was done using standard microbiological methods. Molecular characterization and identification of bacterial isolates was done using 16S rRNA gene sequencing method. Antibiotic sensitivity was carried out on bacterial isolates using disc diffusion method. Plasmid profile of drug resistant isolates was done using alkaline analysis method. Comparison of means was done using Analysis of Variance. Antibiotic residues were detected in 10 (50%) of the 20 milk brands analyzed. The residual levels of tetracycline, oxytetracycline and chlortetracycline ranged between 5ng/kg and 1569ng/kg while none of the samples had doxycycline residues. The prevalence of tetracycline residues in evaporated milk brands and powdered milk samples were 100 and 23 % respectively. The aerobic plate counts ranged from 2.5 × 102 to 6.5 × 102 CFU∕mL for evaporated milk and 2.5 × 101 to 6.0 × 101 CFU∕mL for powdered milk. A total of ten bacterial species were isolated and identified. Susceptibility result showed that 95% of the isolates were sensitive to erythromycin, cefuroxime and gentamycin; 12.5% were resistant to tetracycline and ampicillin, 10% were resistant to ofloxacin and 7.5% to doxycycline and penicillin. Five of the bacterial isolates were resistant to more than one class of antibiotics. Resistant isolates subjected to plasmid profiling had detectable plasmids with estimated sizes between 120bp and 1000bp. The obtained results provide evidence that the presence of antibiotic residues in evaporated and powdered milk is an indication that the public is exposed to the harmful effects of the residues.

Probiotics are widely used in different forms of food or food supplements due to their health benefits. Probiotics consumption has seen an increase over the years. The main species used in probiotic products are Lactobacillus and Bifidobacterium, along with other species such as Bacillus. Generally, probiotic microorganisms are accepted as safe even though they are resistant to several antibiotics. Some probiotic strains with intrinsic antibiotic resistance may be beneficial in regenerating gut microbiota during antibiotic therapy. However, the antibiotic resistance genes identified in probiotic microorganisms may carry the risk of the transfer of resistance genes to pathogens, raising concerns. For instance, tetracycline resistance genes have often been detected in probiotic organisms Bifidobacterium and Lactobacillus. The antibiotic resistance genes carried on mobile genetic elements create reservoirs for pathogen resistance. This transfer of resistant genes to opportunistic pathogens and their spread may pose great danger. Hence, the purpose of this review was to assess the presence of antibiotic resistance in probiotic microorganisms and the potential transfer of the resistant genes to pathogens or commensal bacteria in the intestine.