Asian Journal of Biotechnology and Bioresource Technology

Background: Despite the banned on the use of dichlorodiphenyltrichloroethane (DDT) and other Persistent Organic Pollutants (POPs) by the Stockholm Convention for their toxicity, emerging shreds of evidence have indicated that DDT is, however, still in use in developing countries. This might increase the global burden of DDT contamination and its hazardous effects.

Aim: This study focused on the isolation and characterization of p,p’-DDT-degrading bacterium from a tropical agricultural soil.

Methodology: Standard isolation procedure was used for the screening and isolation of the strain. The 16S rRNA and phylogenetic analyses were used to identify the isolate and established protocols were followed to characterize the strain.

Results: A new strain belonging to the genus Aeromonas was isolated from agricultural soil using minimal salt-p,p’-DDT enrichment medium. The 16S rRNA sequencing was used to identify the strain and the partial sequence was deposited in the NCBI GenBank as Aeromonas sp. Strain MY1. This mesophilic isolate was capable of utilizing up to 50 mgL^-1 of p,p’-DDT as the sole carbon source at an optimum pH of 7.5 and optimum temperature of 35 °C within 120 h under aerobic conditions. Fe²⁺ (0.2 mgL^-1) demonstrated a stimulatory effect on the p,p’-DDT degradation capacity by the strain MY1. However, Zn, Cu, Pb, Hg, Ag and Cr ions have demonstrated various patterns of inhibitory effect on the p,p’-DDT degradation capacity of the isolate at 0.2 mgL^-1. The strain MY1 could be a promising candidate for the bioremediation of p,p’-DDT contaminant.

Conclusion: Aeromonas sp. strain MY1 was capable of utilizing p,p’-DDT as a sole carbon source under aerobic conditions. The utilization capacity of the strain was influenced by some heavy metals. Fe was found to enhance the p,p’-DDT utilization capacity of the isolate at a lower concentration. While Zn, Cu, Pb, Hg, Ag and Cr showed various patterns of inhibitory effect.

The investigation of groundwater contamination from septic tank siting was done in Umungasi/Abayi, Abia State. The aim of this study was to investigate the effect of siting septic systems on the quality of groundwater in Umungasi, Abayi, Aba. Twenty (20) water samples were randomly collected from boreholes located less than 30 m away from septic systems in Umungasi, Abayi Aba, Nigeria to determine their physico-chemical and heavy metals characteristics. While three (3) water samples at distances ranging from 60 m from the nearest septic system were sampled for analyses as controls. Standard analytical techniques were employed in the investigation. The result showed that most of the physicochemical parameters analysed in the borehole water samples were within the WHO/SON/NAFDAC recommended limits except for pH in BH4 and BH7 which had values of 6.3 respectively and were not within the WHO/SON/NAFDAC standard limit of 6.5-8.5. Some of the heavy metals analysed during the period of study were within the permissible limits except for iron in BH5 (0.443 mg/L), BH7 (0.367 mg/L), BH8 (0.511 mg/L), BH9 (0.31 mg/L), BH15 (0.41 mg/L), BH16 (0.327 mg/L), BH17 (0.337 mg/L) and BH18 (0.315 mg/L) that were above the permissible limits of WHO standards of 0.3 mg/l. There was no influence of septic tank siting to the boreholes on groundwater quality during the period of study even though the distance of septic tanks from boreholes in the areas investigated did not conform with that recommended by WHO of 30 – 40 m. The contamination is from the general unhygienic condition of the environment.

The current study investigated the effect of selected local herbal plants on the quality and physical organoleptic taste of cow milk. In total, three medicinal plants namely Solanum schimperianum hochst (Zitoun), Olea europaea L (Hadeq) and Acacia etbaica schweinf (Kasha) were chosen. Five different farms in Aljfarah district were selected in the study. Approximately, 5gm of leaves from each plant were collected, cleaned and dried then crushed into powder. A 1800 ml milk sample was collected from the whole-milk container of each farm. 200 ml was used for each treated and control group. A standard fumigation process using charcoal fire was performed on each treated group using the prepared plant powder. The quality of treated milk against each tested plant was estimated by physical testings’ using gustatory and olfactory rank using 45 participants. In total, 40.9% of participants ranked Solanum schimperianum hochst as their first best choice followed by 34.8% for Olea europaea L and 23% chose Acacia etbaica schweinf. Fifty percent of participants have reported better quality of taste and odour of treated milk comparing to control groups. Also, 82% of participants expressed their confidence regarding the effectiveness of herbal plants in improving the quality of milk. In conclusion, herbal plants improved the quality of milk and limited the spoilage process, showing the potential application of herbal plants in milk industry.

Spirulina is a type of blue-green microalgae also is a type of cyanobacteria. This was established in 1967 as a "wonderful future food source". It is a rich source of minerals, vitamins, nutrients, protein, carotenoids, and essential amount of amino acids. Spirulina also a good source of antioxidants. It can protect against oxidative damage. It activates cellular antioxidants enzymes. Inhibits lipids peroxidation and also DNA damages, scavenges, free radicals, and increase the activity of superoxide dismutase and also catalyze. The Spirulina supplements seem to be affected more effectively the innate immunity and promoting the activity of natural killer cells. Also it has a high potential capacity to increase immunity power to suppress viral infections, and it is well known to be a healthy addition to one's diet. It is most commonly used as a natural dietary supplement. There is a main active compound called phycocyanin. It is a pigment-protein complex. This pigment used mainly as natural colouring in food industry. Spirulina is well tolerated when grown at under controlled conditions. Also it can be grown as a pure culture alkaline water. Spirulina products have bioactive protein with the ability to stimulate the intestinal immune system. This is available in many forms such as spirulina powder, capsules, etc and this products has many mediational uses.

High protein from meat consumption has been associated recently to environmental depletion and health related issues despite the important contribution of meat and meat products in diet and growth development. This has motivated debates on a drastic shift from excessive meat consumption amongst stake holders, academics, animal rights activists and environmentalist as informed consumers are pushing food scientist for a more sustainable alternative protein source. Plant proteins are considered a suitable alternative protein. However, the nutritional, functional potential and the form of presentation have shown some technological difficulties which indicates that direct transformation of plant proteins to meat products is less feasible. Though meat alternative research is promising in developed countries, there are technological breakthroughs that have permitted to replace in part or fully certain sensory attributes of meat inspired by the technology behind the ancient east Asian traditionally structured products like tofu, seitan and tempeh. However, despite the global increase in meat consumption associated with high standard of living, the search for the meat protein alternative from plant products have been limited to the conventional sources of soybeans, beans, lentils, vegetables and pulses. Future research could be diversified and orientated towards improving the existing African foods produced endogenously from wild orchid tubers widely consumed in low middle income countries in the form of cakes, meat substitutes, fake meat, mock meat and/or meat replacements. The successful production of a convenient and acceptable plant-based meat replacement will go a long way to reduce or eliminate excessive meat consumption. This review is geared towards a wider data search concerning the advances in meat alternative research and particularly to illustrate on some neglected African endogenously processed products consumed as meat alternatives that needs further research on the wild tubers sources as ingredients for potential convenient and acceptable meat alternatives or extender.