Browsing by Author "Agwa, Obioma"

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    Antimicrobial Activity and Toxicity of Sophorolipids Produced by Candida haemulonis and Saccharomyces cerevisiae against Some Selected Microorganisms
    (Sciencedomain International, 2021-11) Williams, K. F.; Agwa, Obioma; Abu, Gideon O.
    Sophorolipid have been identified to possess varying antagonism relationship to a number microbiota, although having been identified as being ecologically friendly. The biosafety of biologically synthesized materials has been identified as a major challenge to commercialization and scale-up. Sophorolipid was produced by Candida haemulonis and Saccharomyces cerevisiae in Palm oil mill effluent impacted soil in Emohua, Rivers State. Submerged fermentation was employed in the production of the sophorolipid while the Well-in-agar approach was employed in the antimicrobial susceptibility was conducted using 20%, 40%, 60%, 80% and 100% on both beneficial and pathogenic bacteria and fungi namely Staphylococcus sp, Nitrobacter sp, Klebsiella sp, Bacillus sp while the fungal flora were Aspergillus sp, Penicillium sp, Rhizopus sp, Candida sp, Mucor sp and Saccharomyces sp. Acute toxicity was conducted using Nitrobacter sp, Nitrosomonas sp and Thiobacillus sp. Probit based determination of acute toxicity after a 48hr and 96hr exposure to the test organisms. Antagonistic nature of the sophorolipids showed there was little or no antagonistic activity on the bacterial isolates than the fungal isolates. The sophorolipid formulation synthesized from both isolates were observed to have a zone of inhibition between 10 mm to 24 mm for Nitrosomonas sp. while to Aspergillus sp it had a range between 4.0 mm to 13.0 mm. Acute toxicity of sophorolipid produced by Candida haemulonis against Nitrosomonas sp 0.054 mg/L while to Thiobacillus sp it had an acute toxicity index of 0.107 mg/L. This study identified that the sophorolipid produced by the yeast isolate had the potential of being employed in a number of sectors. This study has pioneered the untapped benefits in the POME-induced flora and how they can be veritable tools in the biotechnology industry.
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    A Kinetic model for submerged citric acid production by Aspergillus versicolor using oil palm empty fruit bunch
    (Creative Commons, 2021-10) Asoka, Mina; Abu, Gideon Orkwagh; Agwa, Obioma
    The fermentation kinetics of citric acid by Aspergillus versicolor was studied in a submerged batch system. The logistic equation for growth, the Luedeking–Piret equation for citric acid production and modified Luedeking–Piret-like equation for glucose consumption was proposed for this study. The model appeared to provide a reasonable description for each parameter during the growth phase. The production of citric acid was growth-associated.
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    Kinetic Modelling of Oxalic Acid Production from Cassava Whey by Aspergillus niger
    (2021-10) Chioma, Dennis; Abu, Gideon O.; Agwa, Obioma
    The transition from eco-harmful chemical processes to bio-based production of organics has been challenged by the complex nature of fermentation processes. The growth kinetics and modelling of oxalic acid production from cassava whey by Aspergillus niger (MW188538) was studied in a batch fermentation system. The production kinetics of the fermentation study was fitted into the Monod, Leudeking-Piret and Andrews kinetic models. The oxalic acid, reducing sugar, cell dry weights were determined according to the experimental design. The results showed that the production of oxalic acid was associated with A. niger with significant R2 value of 0.96 and growth rate of 0.065 biomass/day using the cassava whey as a sole carbon source. The substrate consumption rate of 14.28 and 11.16 mg/g/day with an R2 value of 0.94 and 0.96 suggest there was a healthy utilization of the Cassava whey and yeast extract as described by the Leudeking-Piret and Monod models.
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    Screening of Agricultural Wastes for Substrates in Oxalic Acid Production Using Aspergillus niger
    (Sciencedomain International, 2021-10) Chioma, Dennis; Abu, Gideon O.; Agwa, Obioma
    The disposal and attendant problems associated with agro-wastes have remained a challenge to the environment. Three agricultural wastes (cassava whey, banana peels and groundnut shells) were collected from the Choba and Yam zone markets in Rivers State, Nigeria and screened for their potential as substrates in the formulation of fermentation media to produce oxalic acid. The inoculum for the study was isolated from the banana peels and identified using the megablast search for highly similar sequences from the NCBI non-redundant nucleotide database. The microbial load and proximate composition of the substrates were determined, and the fermentation media formulated. The organism used for the study was identified as Aspergillus niger MW188538. The results showed a total bacterial count of 9.5x104 cfu/ml, 1.87 x 105 cfu/ml, and 4.0 x 104 cfu/g for cassava whey, banana peels and groundnut shell respectively. The carbohydrates of the cassava whey, banana peels and groundnut shells were 67.74 %w/v, 53.24%w/v and 38.8% w/v respectively. After 12 days of fermentation, the substrates from cassava whey, banana peels, groundnut shells accumulated 2.5 ppm, 1.8 ppm and 1.3 ppm of oxalic acid respectively. The study hypothetically indicates that agro-wastes could be utilized as media components for production of industrial organics.
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    Screening, Characterization and Identification of Sophorolipid-Producing Yeast Isolated from Palm Oil Effluent Polluted Soil
    (Sciencedomain International, 2021-11) Williams, K. F.; Agwa, Obioma; Abu, Gideon O.
    This study investigated the screening, characterization and identification of sophorolipid-producing yeast isolated from palm oil effluent polluted soil. Place and Duration: Two soil samples impacted with palm oil mill effluent were obtained from Elibrada and Rumuche in Emohua Local Government Area, Rivers State, Nigeria, between March 2020 and September 2021. Methodology: The soil samples were analyzed for physicochemical, geotechnical and microbiological qualities. The yeast isolates were identified using biochemical and 16S ITS molecular approaches. The isolates were screened for hydrocarbon degradation and sophorolipid production. The sophorolipid production was evaluated using emulsification index (E24), haemolytic activity, oil spread activity, drop collapse and blue agar plate assay (Cetyl trimethyl ammonium bromide CTAB Method). Results: The pH of the Palm oil mill effluent -impacted soil ranged between pH 6.18 to 6.34 the electrical conductivity value for Elibrada and Rumuche were 20.84 µS/cm and 80.19 µS/cm respectively while that of the unpolluted soil was 220.13 µS/cm. Permeability of the soil from Elibrada was 2.7 cm/s, Rumuche had 1.3 cm/s while the unpolluted soil had 5.6 cm/s. Total organic carbon for soil samples from Rumuche was 4.92%, Elibrada had 6.13% while the unpolluted soil had 8.74%. Oil and grease component for the Rumuche soil was 10500 mg/kg, Elibrada had 7200 mg/kg and the unpolluted soil had 28.0 mg/kg. Total fungal count for Rumuche soil samples was 3.8 × 104 CFU/g while Elibrada had 3.2 × 104 CFU/g. Eighty percent (80%) of the isolates were Candida spp. while 20% were Saccharomyces sp. There were four bands separated which were denoted as ITS 600bp and a Ladder L which was 500bp. The phylogenetic construct showed that the Y8 was 70.2% similar to Candida parapsilosis. The isolate Y3 was 95.8% similar to Candida haemulonis. Isolate Y9 had 100% similarity with Pichia kudriavzevii while Y13 had a 97.4% identity with Saccharomyces cerevisiae the GENBANK accession numbers were Candida haemulonis MW182014, Candida parapsilosis MW182015, Pichia kudriavzevii MW182016 and Saccharomyces cerevisiae MW182017. Conclusion: There is an increasing concern to develop a process for microbial isolation and characterization for effective biotechnological advancement using impacted environmental media as a bioresource.