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The decolourising potential of some laccase-producing Curvularia and Paradictyoarthrinium species
(Discovery, 2026-03-07) Fasiku, Samuel Adedayo; Akinrinsade, Godwin Adeoluwa; Aregbesola, Seun Angel; Olajide, Benedicta Oyindamola; Afolabi, Femi Johnson; Adebami, Gboyega Ebenezer
Laccases are enzymes that break down lignin and are also useful in dye decolourisation. This study investigated laccase production by some laccase-producing fungi and evaluated their ability to decolourise dyes. Some fungi with laccase-producing potential were collected and identified using molecular techniques. They were cultivated on various substrates at pH 5 and 6. Laccase production was determined using 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) [ABTS] and guaiacol as indicators. The fungi were grown in fermentation media containing 1 g/L of dyes, and their decolourising capacity was determined. The fungi were identified as Paradictyoarthrinium diffractum AP3, Paradictyoarthrinium diffractum AP2, Curvularia lunata DP1, Curvularia lunata FESAMB, Curvularia petersonii K2, and Curvularia verruculosa K6. There was higher laccase activity in substrates containing lignin than in those without. The highest laccase production (39.62 U/mL) was recorded by Curvularia lunata DPI in maize straw-containing medium at pH 6 with ABTS as an indicator. In comparison, Curvularia petersonii K2 was the best producer of laccase (17.67 U/mL) when guaiacol was used. Paradictyoarthrinium diffractum AP2 decolourised methyl red, Congo red and safranine, whereas Curvularia lunata FESAMB achieved the highest decolourisation rate (63%) of Leishmann blue. Curvularia and Paradictyoarthrinium species used in this work produced laccase
enzymes, and successfully decolourised dyes.
Optimisation of laccase production by Curvularia verruculosa UDY through solid-state fermentation using response surface methodology
(Discovery, 2026-04-07) Fasiku, Samuel Adedayo; Oladunni, Atilade Amos; Fasiku, Taiwo Bukola; Ernest, Godswill Uduak; Adeogun, Opeyemi Janet; Afolabi, Femi Johnson
Laccases are multicopper oxidase enzymes with significant industrial and environmental applications, including bioremediation, textile dye degradation, and biosensor development. This study aimed to optimise laccase production under solid-state fermentation using Response Surface Methodology (RSM) and to utilise the produced laccase for dye decolourisation. The laccase-producing fungus was molecularly identified. Parameters, including incubation period, pH, substrate concentration, inoculum size, and carbon sources, were optimised using RSM. The model equation was generated using Design Expert, and the model's statistical significance was evaluated using analysis of variance (ANOVA). Laccase was quantified using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) as a substrate. The effect of environmental conditions on laccase activity was determined, and the enzyme was used to decolourise dyes. The laccase-producing fungus was identified as Curvularia verruculosa UDY (accession number PV669996). The optimum laccase yield (735 µU/L) was observed with sugarcane bagasse as the substrate on a basal medium containing a glucose carbon source, at an initial pH of 3, with an inoculum size of 2 fungal plugs, over a fermentation period of 10.5 days. All cations tested enhanced laccase activity, with Mn²⁺ producing the greatest stimulation (1056 µU/mL). At various pH levels, the highest laccase activity (898 µU/mL) of C. verruculosa UDY was observed at pH 9.5, while activity at different temperatures peaked (943 µU/mL) at 60°C after 40 min. Laccase decolourised Congo red by 22% within 2 hours. The production of laccase by C. verruculosa UDY through solid-state fermentation was optimised. Cations, pH, temperature, and time affected laccase activity, and the produced laccase decolourised dyes, which could promote the utilisation of agrowastes for industrial enzyme production as well as laccase decolourisation application in the textile industry.
FORTIFICATION OF BREAD WITH THE SCLEROTIA OF PLEUROTUS TUBERREGIUM
(Food and Environment Safety Journal, 2026-03-31) Afolabi, Femi Johnson; Jegede, Oluwafemi Victor; Babaniyi, Babafemi Raphael; Fashogbon, Racheal Oluwayemisi; Fasiku, Samuel Adedayo
Bread is a staple food in most parts of the world. In Nigeria, it is the second most consumed food after rice. However, grains used in the production of bread, such as wheat, millet, maize, and others, are known to be poor in protein; therefore, bread is also low in protein content. This study aimed to supplement wheat flour with flour made from the sclerotium of Pleurotus tuber-regium to enhance the nutritional value of bread. Wheat flour was supplemented with different concentrations of Pleurotus tuber-regium sclerotium flour (5-25%), while 100% wheat and 100% flour served as positive and negative controls, respectively. Evaluations such as dough rising, product weight, sensory parameters, and proximate composition were carried out. Data were analysed using analysis of variance and the Spearman correlation coefficient. The supplementation negatively affected the rising of the dough from 1.2 (5% supplementation) to 0.4 (25% supplementation) after 25 minutes of incubation, but positively influenced the weight of the products from 348 g (non-supplemented sample) to 495 g (100% sclerotium flour). The bread with the lowest level of supplementation (5%) had the highest acceptability (5.31); however, further increases in supplementation reduced acceptability. The supplementation improved the protein, fat, and ash contents, and decreased the moisture, crude fibre, and carbohydrate contents of the bread. Overall, the supplementation appeared to improve the nutritional composition of the bread while also enhancing its shelf stability, as moisture content decreased with higher supplementation. Additionally, it suggests a viable use of the sclerotium in producing composite flour for bread making.
Microbial Insecticides in Sustainable Agriculture: Mechanisms, Applications, and Future Prospects
(Ajayi Crowther Journal of Pure and Applied Sciences, 2026-05-04) Fasiku, Samuel Adedayo; Akagbosu, Adesuwa Oluwatofunmi; Afolabi, Femi Johnson; Afariogun, Moses Sunday
The current research work examines microbial insecticides as potential and sustainable alternatives to chemical pesticides for agricultural pest management. The development, mechanisms, and use of bacterial, fungal, viral, and protozoan pesticides are studied with particular attention to mode of action and specificity. The review explains that toxins produced by important bacteria, such as Bacillus thuringiensis (Bt), damage cells, and toxins from fungi, such as Beauveria bassiana, penetrate and colonise insects, rendering them ineffective. Microbial pesticides have many advantages, including negligible pollution, safety to non-target organisms, and a low likelihood of pest resistance development. Microbial insecticides are complex in nature but degrade rapidly. The review also covers production methods, application techniques, and quality control measures needed for effective use in integrated pest management. Although microbial pesticides can be an environmentally sound solution for sustainable agriculture, their use must be designed taking into consideration the formulation, application, and environmental conditions.
Probiotic Capability of Bacillus spp. Isolated from Iru - Fermented African Locust Bean (Parkia biglobosa)
(EC Microbiology, 2022-05-31) Olanbiowninu, Afolake; Esho, Deborah; Osinupebi, Ayooluwa; Awotundun, Theresa; Fasiku, Samuel
Bacillus species have diverse applications in agriculture, enzyme production and medicine to produce vaccines and probiotics. Currently, little is known about the probiotic potential of Bacillus from fermented condiments of African origin. This work aimed at isolating Bacillus spp. with probiotic potential from fermented African locust bean - iru. Iru samples were obtained from a local market in Oyo, Nigeria. The samples were pretreated by boiling to eliminate vegetative cells and inoculated using pour plate technique. Isolates were identified; their antibiotic susceptibility profile and antimicrobial activity against known pathogens (Listeria monocytogenes, Salmonella enterica and Staphylococcus aureus) were determined. Safety and technological properties (cellulase, protease, lipase and amylase activities) of the isolates were also determined. Twenty spore-forming, Gram-positive with rod shape were isolated and identified as Bacillus subtilis (8), Bacillus licheniformis (4), Bacillus pumilus (3), Bacillus polymyxa (1), Bacillus licheniformis (1), Bacillus alvei (1), Bacillus badius (1) and Bacillus sp. (1). All isolates were susceptible to levofloxacin, ciprofloxacin, ofloxacin, gentamycin and azithromycin while 16 (80%) were resistant to cefotaxime. Only 11 (55%) isolates inhibited the growth of Listeria monocytogenes, with no inhibition recorded against other pathogens. The 11 isolates synthesized at least one enzyme, with B. subtilis PA1 and B. alvei PB5 producing the four enzymes determined. γ-haemolysis was exhibited in 90% of the isolates while 10% exhibited α-haemolysis. Bacillus subtilis PA1, Bacillus subtilis PA6 and Bacillus licheniformis PA5 survived high acid, bile and simulated acid and bile. Bacillus subtilis and Bacillus licheniformis from African fermented locust beans have excellent probiotic potentials.