Browsing by Author "Odunfa, Sunday Ayodele"
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Item Enhancing the Production of Reducing Sugars from Cassava Peels by Pretreatment Methods(International Journal of Science and Technology, 2012) Olanbiwoninu, Afolake Atinuke; Odunfa, Sunday AyodeleCassava peel is one of the major biomass wastes in Nigeria obtained from production of cassava tuber for human consumption, starch production and industrial uses. The objective of this work was to investigate the optimal condition for pretreating cassava peel with dilute sulphuric acid, methanol with catalyst (organosolv) and alkali prior to microbial enzymatic hydrolysis for the production of fermentable sugars. The pretreated samples reducing sugar yield was measured after enzymatic hydrolysis. The result shows that acid hydrolysis using sulphuric acid at a concentration of 0.1M at 120oC for 30 min gave a maximum reducing sugar yield of 88.8% and 98%, followed closely by methanol treated peels (78 and 98% ) while alkali pretreated peels produce the least (66 and 88%) for Pseudomonas flourescens and Aspergillus terreus respectively. In this study, H2SO4 and methanolysis treated peels prior to enzymatic hydrolysis had a greater capacity for hydrolyzing cassava peels than NaOH and also combination of pretreatments method with enzymatic treatment is an alternative to improve efficiency of reducing sugar production from cassava peel.Item Folate Enrichment of Ogi (a Fermented Cereal Gruel) Using Folate Producing Starter Cultures(Advances in Microbiology, 2019) Okoroafor, Ike; Banwo, Kolawole; Olanbiwoninu, Afolake Atinuke; Odunfa, Sunday AyodeleThis study was aimed at selecting starter cultures for bio-enriching ogi (fermented cereal gruel) using folate-producing microorganisms. The folate-producing microorganisms were isolated by incorporating folate analogue, methotrexate in the isolation medium and further screened for folate production by growth in Folic Acid Casei Medium. Folate production was quantified using 3-aminophenol spectrophotometric method. Folate-producing lactic acid bacteria from fermenting maize slurry were species of Lactobacillus, Lactococcus, Pediococcus and Leuconostoc while yeast isolates were mainly species of Candida and Saccharomyces. However, Lactobacillus plantarum X13, Pediococcus pentosaceus L73, Candida parapsilosis Y77 and Candida tropicalis Y74 were used as starter cultures singly and in combination for the fermentation and production of ogi. The highest folate concentration, 30.97 ± 0.37 μg/ml, was observed after 24 h of the co-fermentation of maize slurry with Lactobacillus plantarum X13 and Candida tropicalis Y74. This represents a triple fold of the folate concentration observed in unfermented maize slurry. The pH of the fermenting maize slurry was observed to decrease from 6.12 to 3.60, while the reducing sugars and the titratable acidities were observed to increase as fermentation progressed. Sensory evaluation of the ogi samples after fermentation showed high general acceptability comparable to the naturally fermented ogi as regards to colour, taste, flavour, aroma and texture. The data made available in this study suggest the possibility of folate enrichment of ogi and its use as a vehicle for increasing folate availability to consumers thereby preventing folate deficiency diseases prevalent in many African countries.Item Polyphasic characterisation of Bacillus subtilis strains for iru fermentation and vitamin bioenrichment(2026) Awotundun, Theresa Abimbola; Greppi, Anna; Pugin, Benoit; Plüss, Serafina; Odunfa, Sunday Ayodele; Russo, Pasquale; Bokulich, Nicholas A; Olanbiwoninu, Afolake AtinukeBacillus subtilis plays a key role in traditional plant fermentations in Africa and Asia. Here, we characterised B. subtilis strains isolated from iru, a fermented condiment from Nigeria, and evaluated their potential as riboflavin- and folate-producers. Eighty-six Bacillus spp. were isolated through heat treatment and spore plating on nutrient agar. The isolates were phenotypically identified, assessed for enzymatic activity (proteases, amylases), and tested for safety (haemolysis, gelatinase, and biogenic amine production). Selected isolates were further screened for riboflavin and folate production in chemically defined media. Thirty-four strains were phenotypically identified as B. subtilis with riboflavin production ranging from 0.006 to 0.039 mg L−1, while nine produced folate between 0.300 and 1.940 mg L−1. These strains were submitted to the selective pressure of toxic analogues of riboflavin and folate in order to enhance their capability to synthesise these vitamins, with the best strain showing increases from 0.013 to 0.020 mg L−1 for riboflavin and 1.665 to 3.715 mg L−1 for folate. The most promising candidates were employed for lab-scale iru fermentation. In lab-scale iru fermentation using the improved strains, vitamin levels were enhanced by 38% for riboflavin (0.036 to 0.050 mg g−1 of iru) and 35% for folate (0.035 to 0.047 mg g−1 of iru), signifying that 10 g of iru fermented with these strains can provide 25% of daily riboflavin intake and 100% of folate intake. These results highlight the potential of selected B. subtilis strains as functional starter cultures for the dual purpose of iru fermentation and vitamin biofortification. Such strain selection and optimisation represent a promising biotechnological strategy to enhance the micronutrient profile of traditional fermented foods while preserving their sensory and cultural value.Item Production of Cellulase and Xylanase by Aspergillus terreus KJ829487 Using Cassava Peels as Subtrates(2016) Olanbiwoninu, Afolake Atinuke; Odunfa, Sunday AyodeleCassava (Manihot esculenta, Crantz) is one of the most important food plants in West Africa. Its peels are made up of cellulose, hemicellulose and lignin. This lignocellulolytic biomass can be converted using microbial enzymes to fermentable sugars which have wide range of biotechnological relevance in many fermentation processes. The aim of this study is to screen filamentous fungi from decaying cassava peels that are good producers of xylanases and cellulases. Decaying parts of cassava peels were obtained and brought to the laboratory for further work. Fungi were isolated, identified and screened for cellulase and xylanase production. Isolate with highest frequency of occurrence and enzyme production was identified using phenotypic and molecular method. Optimisation of growth conditions for enzymes production was monitored using the DNSA method, also saccharification of cassava peel were carried out using the enzymes obtained from the isolate. Aspergillus terreus KJ829487 was the predominant fungus. It produces cellulases and xylanases optimally at 40°C, pH 6 and 8, utilising carboxymethylcellulose (CMC) or xylose and yeast extracts as its carbon and nitrogen sources respectively. Saccharification of the peels yielded 584 mg/L glucose, 78 mg/L xylose and 66 mg/L rhamnose. Aspergillus terreus KJ829487 obtained from cassava peels have the ability to produce high concentration cellulases and xylanases which effectively hydrolysed the lignocelluloses’ biomass to fermentable sugars.Item Production of Fermentable Sugars from Organosolv Pretreated Cassava Peels(Advances in Microbiology, 2015) Olanbiwoninu, Afolake Atinuke; Odunfa, Sunday AyodeleCassava peels are rich in lignocellulolytic materials which are not readily amenable to enzymatic hydrolysis; hence, there is a need for a suitable pretreatment method that will support enzymatic hydrolysis. This study was designed to investigate lignocellulolytic organisms that would effectively support the bioconversion of organosolv pretreated cassava peels to fermentable sugars. Decaying cassava peels were collected into sterile bottles and microorganisms isolated, characterized and screened for lignocellulolytic enzymes production. Optimum temperature, pH and nutrient sources for enzyme production were determined. Organosolv pretreatment was carried out using methanol with varied concentration of catalyst (0.01 - 3 M), reaction time (15 - 60 min) and substrate size. Crude enzymes (cellulase and xylanase) from the isolates were added to the pretreated peels and bioconversion was monitored by measuring the concentration of reducing sugar and calculating the percentage peel hydrolysis. The fermentable sugars produced were quantified using gas chromatography. Pseudomonas fluorescens and Aspergillus terreus were isolated. P. fluorescens produces 2.8 u/mL of crude enzymes optimally at 50°C and pH 8 while A. terreus produces 3.4 u/mL optimally at 40°C, pH 6. Both isolates utilizes CarboxyMethylCellulose (CMC) and yeast extract as their best carbon and nitrogen sources. Highest percentage of peel hydrolysis was 67% for P. fluorescens at 0.01 M and 0.05 M for A. terreus (94%). Highest concentration of fermentable sugar was produced by A. terreus crude enzyme (331.79 mg/L glucose, 45.3 mg/L rhamnose and 46.52 mg/L xylose). P. fluorescens and A. terreus effectively supported the bioconversion of organosolv pretreated cassava peels to fermentable sugars.Item Riboflavin enriched iru: A fermented vegetable protein(2017) Olanbiwoninu, Afolake Atinuke; Irokosu, Olaoluwa; Odunfa, Sunday AyodeleAfrican locust bean (Parkia biglobosa) cotyledon is fermented in most countries of West Africa to produce a soup condiment, known as ‘iru’ in Yoruba language, or ‘dawadawa’ in the predominant Hausa language. Iru is rich in minerals and serves as a source of protein supplement in the diet of poor families. Riboflavin (Vitamin B2) is an essential component of basic cellular metabolism but its daily requirement is not met in Nigeria particularly among the rural dwellers. Therefore, the provision of a riboflavin enriched iru will help to eradicate problems encountered from riboflavin deficient diet. Iru was purchased from three different markets in Ibadan, Oyo State, Nigeria. From the iru, microorganisms were isolated, characterised, screened for riboflavin production and co-cultured for the production of riboflavin enriched iru. Sixty-three bacteria were isolated and identified as Micrococcus varians (9), Staphylococcus species (27), Bacillus species (24) and Micrococcus luteus (3). Bacillus subtilis IR50 produced highest riboflavin 25.77 mg/L, followed by Staphylococcus spp. strain IR26 23.37 mg/L, while M. varians IR49 had the least riboflavin production 6.35 mg/L. Mixed culture of B. subtilis IR50 and Bacillus licheniformis IR28 produced the highest riboflavin of 4.5 mg/L, Staphylococcus aureus IR06 and B. subtilis IR50 produced 2.3 mg/L, while B. subtilis IR50 produced 1.5 mg/L when used singly. The result shows that B. subtilis IR50 have the potential to increase the riboflavin content of iru and therefore will contribute to bioenrichment technology.