Nigerian Journal of Biotechnology

Biodegradation potentials of edaphic bacterial isolates cultured on Haloxyfop R Methyl ester herbicide-mineral salt medium

2024-01-31T07:02:18+00:00

The heterotrophic and haloxyfop-R methyl ester utilizing bacterial counts associated with top soil samples was evaluated. Three (3) bacterial isolates; Bacillus sp., Micrococcus sp. and Staphylococcus sp. were cultured and screened for their ability to utilize haloxyfop-R methyl ester as sole source of carbon and energy using the turbidimeteric procedure. The growth profiles of two axenic cultures; Bacillus sp. and Micrococcus sp. were determined using the shake flask test. Parameters which included pH, mean viable bacterial counts, optical density and dissolved CO₂ were determined during growth profiling using relevant procedures and equipment. The pH of the soil samples was 5.08 ± 0.02 for sample A and 4.62 ± 0.02 for sample B. The total heterotrophic bacterial count was 2.8 × 10⁴ cfu/g ± 849 for A and 4.62 × 10⁴ cfu/g ± 989 for B. The mean dissolved CO₂ data for Micrococcus sp. during the growth profile study ranged from 1.1 mg/l ± 0.1 to 6.8 mg/l ± 0.2. Axenic Micrococcus sp. was the most effective amongst the growth profile cultures in mineralizing the herbicide content of the culture medium.

Optimization of culture conditions for xylanase production by mixed fungal fermentation: Effects on pretreated maize cobs

2024-01-31T07:07:10+00:00

The use of microorganisms for xylanase production plays important role in the bioconversion of lignocelluloses and also required in huge amount for industrial level application. This necessitates the need to select potent microorganisms for xylanase production, followed by optimization of media components for enhanced production. The effects of altering cultural fermentation conditions on the xylanase production ability in maize cobs were investigated. A consortium of four fungi; Lenzites betulina, Trichoderma reesei, Lachnocladium specie and Aspergillus niger were used to carry out single and mixed solid-state fermentation on NaOH pretreated maize cobs. Optimization of fermentation factors were carried out from ten groups of individual and co-fermented fungal combinations. L. flavidum was found to be the most effective xylanase producer with optimal conditions at pH of 5.5, moisture 75%, inoculum concentration at 5-6 x 10³spores/ml, incubation period of 7-9 days and 1% peptone as the best nitrogen media supplement. Variation to different degrees in the degradation of the maize cobs were observed. A 10% decrease in cellulose was observed with co- cultures of T. reesei and A. niger and a 15% decrease in the hemicellulose fraction. The biotechnological potential of corn cobs has been enhanced by the screening and optimizing the culture conditions.

Review of Nigeria biosecurity architecture: Prospects, challenges and awareness

2024-01-31T07:12:19+00:00

Ensuring immediate and effective biosecurity in Nigeria has become imminent following the turnover of events within Nigeria and the globe. These emanating events such as emerging and reemerging diseases, both in human health, agriculture and the environment, signal for safety towards one health approach. They also call for the need to ensure that the next outbreak of infectious diseases or reemerging global pandemic does not emerge from our environment or bioengineered by one of us in quest for research output. This fundamental has enabled us to review some identified issues and proffering possible recommendations.

Eco-toxicity assessment of fossil fuel tainted soil before phytoremediation trial

2024-01-31T07:17:40+00:00

The research objective was to assess the extent of fossil fuel toxicity in the contaminated soil for an improved appraisal before phytoremediation trial and eco-safety of the soil. We used Bonny light fossil fuel to contaminate soil at different percentage levels of concentrations (5%, 3%, 1% and 0%). We assessed earthworm weight change and survival rate and plant response of Zea mays to the various treatments. Our results show that soil treated at concentration level of 5% had the highest earthworm mortality rate while the control soils had the highest earthworm survival rate. In addition, there was a noticeable change in the body weight of surviving earthworms in the 5% and 3% treated soil. Germination, shoot length and root length of the experimental plant was not totally inhibited in all the different concentrations. There was greater germination percentage obtained in 3%, 1% and 0% fossil fuel concentrations. The study verifies that high fossil fuel contamination percentage affects the biota of the soil by inhibiting plant germination and growth as well as reducing the survival and body mass of earthworms in the soil. The petroleum oil percentages utilized in this investigation can support phytoremediation trial and proposes that petroleum oil soil contamination ≤ 3% is ecologically safe for plants and animals’ survival as well as development.

Probiotics screening from selected Nigerian prebiotics: Alternative starter culture sources for yoghurt production

2024-01-31T07:21:36+00:00

The rise of functional foods has expanded food production, offering not just essential nutrition but also potential health and longevity benefits. This study aimed to identify probiotics from common Nigerian fermented foods as potential starter cultures for yogurt production. Ten local fermented food were screened for suitable starter culture(probiotics) for yogurt production, including fresh milk from cow (CM), sheep (SM), and goat (GM), as well as pap made from maize, millet, sorghum, cassava products (garri, fufu, and lafun), and Kunuzaki. Probiotic isolates with desired characteristics underwent tests for tolerance to acidic pH and bile conditions; antioxidative properties. Test yogurt was produced using Lactobacillus (LAB) isolates and physicochemical and organoleptic scores were determined for the yogurt samples. LAB species from CM, SM, and Lafun samples showed tolerance to both acidic pH (pH 3.0) and 0.5 percent bile. CM isolates exhibited strong antioxidant effects comparable to vitamin C. Yogurt samples had pH ranging from 4.77 to 5.45 and titratable acidity from 5.56 to 8.06. Sensory characteristics of the test yogurt did not significantly differ from commercial yogurt (p ≤ 0.05). Thus, probiotics (LAB) from common Nigerian fermented foods like CM, SM, and lafun could serve as cost-effective, nutrient-rich alternatives for yogurt starter cultures.

Molecular typing of clinical and non-clinical Escherichia coli from Rivers State, Nigeria using amplification-based RAPD and ERIC-PCR typing methods

2024-01-31T07:29:07+00:00

Due to the diverse nature of Escherichia coli, typing of these organisms is essential. This can provide key epidemiological information not just on the strains in circulation and their relationship, but also on the development and spread of drug resistant clones. Affordable PCR-based typing techniques have resulted in an increase in typing studies particularly in resource limited settings. But information from Nigeria on strain typing is limited. This study was therefore aimed at typing clinical and non-clinical strains of E. coli from Nigeria using the PCR based Random Amplification of Polymorphic DNA (RAPD) and Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) typing methods.

E. coli was isolated from clinical and non-clinical sources using Eosin Methylene Blue agar. Characteristic green metallic sheen colonies associated with E. coli were purified, identities determined using standard biochemical tests and confirmed using molecular methods. Susceptibility testing was carried out using the modified Kirby-Bauer disc diffusion test and RAPD and ERIC-PCR typing carried out on 48 confirmed E. coli isolates as previously described. ERIC-PCR typing resulted in the generation of 38 unique patterns with a 0.94 diversity. Nine of these were singletons comprised of only a single isolate, while the remaining 29 patterns were grouped to 10 clusters. RAPD gave similar results of 37 patterns, 9 singletons, 0.94 diversity and 13 clusters. For ERIC-PCR, all isolates with identical patterns were from the same source. RAPD, however, had identical patterns present in isolates from different sources.

Using the ERIC-PCR typing method, this study was able to identify non-clinical isolates as distinct from the clinical E. coli isolates as evidenced by 100% identical ERIC-PCR profiles of isolates from the same source and a lack of 100% relatedness in isolates from different sources.

Assessment of normal human breast cells (MCF10A cells)–Surface interactions on porous poly-di-methyl-siloxane (PDMS) structures for potential biomedical applications

2024-01-31T07:57:24+00:00

Biocompatibility stands out as a crucial and fundamental requirement before approval of biomaterials for medical use. The study aimed to evaluate the interaction between normal human breast cells (MCF10A cells) and porous poly-di-methyl-siloxane (PDMS) structures for potential biomedical applications. Preparation and characterization of the PDMS substrate were carried out, followed by the assessment of cell proliferation and fluorescence imaging using an Alamar blue assay and fluorescence microscopy, respectively. The results revealed that initially (at 4 hours post-incubation), there was no notable difference in cell proliferation among the various groups (non-porous PDMS, PDMS_0-150, PDMS_150-250, and PDMS_250500). However, at 48 and 96 hours, a significant increase in cell proliferation was observed in the PDMS_250–500 μm group compared to other groups (P<0.05). Furthermore, the results of the fluorescence microscopy corroborated a substantial enhancement in cell growth and attachment as the porosity of the PDMS substrate increased. However, cells seeded on non-porous PDMS surfaces exhibited a significant decline (P<0.05) in cell growth in both the Alamar blue assay and fluorescence imaging. These findings hold great promise for the creation of surfaces and materials that are specifically designed to influence biological reactions and show potential for a range of biomedical uses.

Enhancing biomedical applications: Modifying porous poly-di-methyl-siloxane (PDMS) structures with magnetite nanoparticles (MNPs) to improve interaction with normal human breast cells (MCF10A cells)

2024-01-31T08:03:12+00:00

The phenomenon of cell-biomaterial interaction is responsible for adherent cells' adhesion to the biomaterial surface and the corresponding cell activities. The study aimed to enhance biocompatibility and versatility by modification of porous PDMS structures with MNPs for their safe interaction with normal human breast cells, MCF10A cell line. Preparation of the MNP-modified porous PDMS substrate was carried out by mixing a silicone elastomer base with a curing agent at a specific ratio, typically in a 10:1, followed by modification with MNP and the creation of pores of different dimensions. The substrate was subsequently characterized with Fourier-transform infrared spectroscopy. Furthermore, the assessment of cell proliferation and fluorescence imaging was done using the Alamar blue assay and fluorescence microscopy, respectively. The result of the study showed that PDMS + MNP (non-porous) did not significantly differ in percentage Alamar blue reduction at 4 hours when compared to PDMS + MNP_0-150, PDMS + MNP_150-250, and PDMS + MNP_250-500. Additionally, all the groups differed significantly (P>0.05) from one another at 48 and 96 h, except the PDMS+MNP_150-250 group compared to the PDMS+MNP_250-500 group, which did not exhibit any significant differences (P>0.05). The result further showed that when compared to all other groups, the fluorescence imaging result revealed that, after 96 h, there was very little cell attachment and proliferation on the surface of PDMS+MNP (non-porous). Other groups demonstrated discernable cell adhesion and proliferation over time. These outcomes demonstrate the significance of porosity in influencing cellular interactions and highlight its role in cell proliferation on biomaterial.

Molecular characterization of biosurfactant-producing bacteria from a crude oil polluted soil in Nigeria

2024-01-31T08:14:59+00:00

Most biosurfactant-producing microorganisms are hydrocarbon degraders. The research was conducted to isolate and characterize biosurfactant-producing bacteria from a crude oil polluted soil in Nigeria. Biosurfactant-producing bacteria were isolated from crude oil-polluted soil. Crude oil-polluted soil was collected by random sampling and its physicochemical analysis was done. Bacteria were isolated from the contaminated soil and screened for biosurfactant production. Organisms that showed the ability to produce biosurfactant were identified using morphological, biochemical and molecular methods. The physicochemical parameters of the soil showed a pH 6.9, electrical conductivity of 71.5, 2.55% carbon, 2.016% nitrogen and 5.98% phosphorus. The values of biosurfactant tests showed that organisms S2 and S13 were positive for biosurfactant production. The percentage emulsion indexes of the two selected organisms S2 and S13 were 59.09% and 57.14% respectively. The Blast analysis from the molecular identification showed that the isolated organisms were Gordonia alkanivorans for S2 and Tsukamurella inochensis for S13. This research showed that the isolated biosurfactant-producing bacteria are abundant in the crude oil polluted soil.

Screening for virulent and antibiotic resistant Escherichia coli in raw and ready-to-eat snails (Arachatina marginata) vended in selected markets in Port Harcourt, Nigeria

2024-01-31T08:18:23+00:00

This aim of this study was to screen for virulent and antibiotic resistant Escherichia coli in raw and ready-to-eat snails (Archachatina marginata) vended in selected markets within Port Harcourt, Nigeria. Proximate composition, isolation, identification and presence of virulent genes were done using standard methods. Raw snails from Choba market had Escherichia coli count ranging from 1.8x10⁴ to 8.2x10⁵ CFU/g, while the ready-to-eat samples were not contaminated with E. coli. Raw snails from Rumuokoro market had Escherichia counts ranging from 4.2 x10⁴ to 6.9 x10⁶ CFU/g while two of the ready-to-eat samples had counts of 3.602 x 10³ CFU/g and 3.556 x 10³ CFU/g. Raw snails from Oyigbo market had Escherichia counts ranging from 4.653 x 10³ CFU/g to 5.579 x 10³ CFU/g while one ready-to-eat sample had Escherichia. Antimicrobial susceptibility testing showed that 100% of Escherichia were resistant to cefuroxime, augmentin, cefixime and ceftazidime. Of the three-virulence genes (eae, ast and aggR) screened for in this study only aggR was detected in one Escherichia isolate. Proper blanching and heating should be employed during preparations of snails to curtail food poisoning.

Polystyrene degradation by bacteria isolated from the larvae of Rhynchophorusphoenicis

2024-03-12T06:06:10+00:00

The larvae of insects of the order Coleoptera have been reported to biodegrade plastics aided by their chewing mouthparts and the activities of their gut biota. However, there is no report of this ability by the African palm weevil (Rhynchophorus phoenicis). This study aims to the ability of R. phoenicis larvae to biodegrade polystyrene (PS). A total of 100 R. phoenicis larvae were fed for 21 days with PS foam, and afterwards, the gut contents of survivors were investigated for possible PS-degrading bacteria. Bacterial isolates were screened for PS biodegradation in an Erlenmeyer flask with PS film as the sole carbon source, in a mineral salt medium (MSM) at a temperature of 30^oC and a pH of 7, for a period of 28 days. The isolates were used for biodegradation assay under the same conditions, for 60 days. The weight of PS films was determined before and after the biodegradation assay. Chemical changes in the films were confirmed by Fourier Transform Infrared (FTIR) spectroscopy. Two bacterial isolates were recovered from the gut of the only surviving R. phoenicis larvae fed with 100% PS. The isolates were identified based on their 16S rRNA sequences as Lysinibacillus macriodes and Pantoea dispersa with accession numbers OQ652017 and OQ652023 respectively. The isolates caused an 8.8% reduction in the weight of PS film and FTIR spectroscopy results confirmed the formation of groups suggestive of degradation products with the carbonyl group showing up as absorption peaks in the range of 1640-1760 cm^-1 and the hydroxylic group at 3000-3700 cm^-1 . The isolates were able to produce polyhydroxyalkanoate (PHA) equivalent to 1.4g/L, under PS degradation conditions. Therefore, coupling the biodegradation of PS with PHAproduction could be useful for the valorization of PS waste.