Diet plays an essential role in human development and growth, contributing to health and well-being. The socio-economic values, cultural perspectives, and dietary formulation in sub-Saharan Africa can influence gut health and disease prevention. The vast microbial ecosystems in the human gut frequently interrelate to maintain a healthy, well-coordinated cellular and humoral immune signalling to prevent metabolic dysfunction, pathogen dominance, and induction of systemic diseases. The diverse indigenous diets could differentially act as biotherapeutics to modulate microbial abundance and population characteristics. Such modulation could prevent stunted growth, malnutrition, induction of bowel diseases, attenuated immune responses, and mortality, particularly among infants. Understanding the associations between specific indigenous African diets and the predictability of the dynamics of gut bacteria genera promises potential biotherapeutics towards improving the prevention, control, and treatment of microbiome-associated diseases such as cancer, inflammatory bowel disease, obesity, type 2 diabetes, and cardiovascular disease. The dietary influence of many African diets (especially grain-base such as millet, maize, brown rice, sorghum, soya, and tapioca) promotes gut lining integrity, immune tolerance towards the microbiota, and its associated immune and inflammatory responses. A fibre-rich diet is a promising biotherapeutic candidate that could effectively modulate inflammatory mediators’ expression associated with immune cell migration, lymphoid tissue maturation, and signalling pathways. It could also modulate the stimulation of cytokines and chemokines involved in ensuring balance for long-term microbiome programming. The interplay between host and gut microbial digestion is complex; microbes using and competing for dietary and endogenous proteins are often attributable to variances in the comparative abundances of Enterobacteriaceae taxa. Many auto-inducers could initiate the process of quorum sensing and mammalian epinephrine host cell signalling system. It could also downregulate inflammatory signals with microbiota tumour taxa that could trigger colorectal cancer initiation, metabolic type 2 diabetes, and inflammatory bowel diseases. The exploitation of essential biotherapeutic molecules derived from fibre-rich indigenous diet promises food substances for the downregulation of inflammatory signalling that could be harmful to gut microbiota ecological balance and improved immune response modulation.

Amylases (EC 3.2.1.1) are cellwall degrading enzymes associated with the pathogenicity of microorganisms in the spoilage of tomato fruits. The use of amylase in many industries has made it very important to optimize production process to achieve maximum yields. Screening and partial purification of Amylase from Aspergillus niger isolated from tomato (Lycopersicon esculentum Mill.) fruits was studied. Amylase producing fungi were isolated from fresh tomatoes kept at ambient temperature (28±1˚C). Isolates were characterized on the basis of their morphological and cultural techniques. Partial purification of amylase was carried out by ammonium sulphate precipitation. The enzyme activity was determined and optimum conditions were obtained. The molecular weights of the crude and partially purified Amylase were determined by SDS PAGE method. A total of five isolates were obtained using basic screening technique for amylase activity, one of the isolates (Isolate code F2) exhibited maximum amylase activity. The fungi isolate code F2 was identified as Aspergillus niger. Optimum conditions for Amylase AMY F2 were ascertained at pH 6.0; temperature 30°C; substrate concentration of 0.3mg/ml, and time of heating of less than 10min. The molecular weights of the crude and partially purified Amylase AMY F2 were found to be 55kDa and 35kDa respectively by SDS PAGE method. Microorganisms had been an encouraging means of economical production of enzymes in large scale for the food and drug industry.

Dietary intake of polycyclic aromatic hydrocarbons (PAH) and heterocyclic amines (HCA) has posted a great health risk as they have been identified as a most potent human carcinogen. Microbial quality of food is also of concern as they contribute to food poisoning and infection. Sixty food samples comprising roasted yam, plantain, grilled and smoked fish and meat were randomly sampled from Lagos and Ogun State, Nigeria, and the PAHs, HCAs contents and microbial load were determined. Isolates were subjected to antibiogram assay. The pH of the samples ranged between 5.08 and 7.49, titrable acidity was in the range of 0.50 and 1.20. Staphylococcus, Bacillus, Micrococcus, Proteus, Pseudomonas, Citrobacter and Klebsiella sp. had been identified. Antibiogram revealed that the isolates were multi-resistant and most resistant to ceftazidime, cloxacillin and tetracycline and more susceptible to ofloxacin. PAHs were detected in some grilled, roasted and smoked samples and with the highest concentrations 314.85 and 139.97 µg/g Dibenzene[a,h]anthracene established in roasted yam and smoked fish samples. Only 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was detected in grilled fish and meat samples. This study therefore established the presence of chemical and microbial contaminants in some of the food items investigated. It recommended that strict sanitary practices and appropriate cooking methods be enforced during food preparation.

Tannase (Tannin acyl hydrolase, EC 3.1.1.20) is an enzyme produced in the presence of tannic acid by various filamentous fungi. They are produced principally by fungi of the genus Aspergillus and Penicillium. The enzyme is used in the food and beverage industry as a clarifying agent for wines, beers and fruit juices. In Africa, billions of dollars are expended yearly on the importation of commercial enzymes for the food and pharmaceutical industries and this increases the cost of production and the finished goods. This study was carried out to isolate tannase producing fungal species using Bambara nuts as a substrate in a bid to finding alternatives to the importation of tannase. Fresh Bambara nuts were collected from different locations in Nigeria. They were cleaned, sorted and intermittently moistened with water to encourage fungal growth for fourteen days. The different fungi obtained after fourteen days were inoculated onto Potato Dextrose Agar plates and incubated at 25°C for five days. Subculturing of fungal isolates was carried out to obtain pure cultures of isolates. Tannilytic activity (hydrolysis of tannin) of isolates was assessed by inoculating them in media containing tannin. The plates were incubated at 25°C for 2-5 days after which the plates were observed and zones of hydrolysis measured. A total of eighteen isolates were obtained. They were all members of the Aspergillus genus. 56% (10) of the isolates were able to degrade tannin acid with mean zone of hydrolysis of 39mm ±23.7 mm (Range 10-70mm). This study established members of the Aspergillus genus isolated from Bambara nuts as viable fungi for application in the production of tannase. This study adds to existing reports on fungal production of tannase.

The need for exogenous phytase in animal feed processing is increasing due to its ability to breakdown anti-nutrients in grains which constitute a large proportion of animal feeds. This study investigated the production of phytase using indigenously isolated Aspergillus sp. and the characterization of the purified phytase. The Aspergillus sp. was isolated from a poultry site using phytate screening medium (PSM). Quantitative estimation of phytase production was carried out using 2 × 10 8 spores/100 mL basal medium containing 0.5% sodium phytate as substrate at 30 °C and 150 rpm for 5 days under submerged fermentation condition. The extracted crude enzyme was purified using ammonium sulphate and gel filtration chromatography using Sephadex G-75 gel. The enzyme was characterized by investigating the effect of temperature, pH, and nutrient sources on the purified enzyme. Molecular identification confirmed the isolate as Aspergillus flavus (accession number of MT899184). The total activity observed in crude faction (609 U/mL) reduced to 187.5 U/mL in the ammonium sulphate fraction and then to 77.6 U/mL in the Sephadex G-75 fraction. Optimum temperature and pH were 40 °C and 6, respectively. The enzyme remained active for 5 min at both 70 °C and 80 °C. However, at 100 °C, all activity was lost. Glucose was the preferred carbon source and had higher activity (0.185 U/mL) but was unable to utilize sucrose. This study concludes that this isolate may be exploited for industrial production of phytase which has great application in animal feed industries.