Ayodeji Amobonye

Potato peels were valorized as a sustainable starch source for the development of functional materials such as bioplastics. Starch was extracted from potato peels (18.75% yield), and subsequently modified via dodecenyl succinylation and acetylation to obtain dodecenyl succinylated starch (degree of substitution (DS) 0.021), acetylated starch (DS 0.67), and two dual‐modified starches with a fixed dodecenyl succinate DS of 0.021 and acetyl degrees of substitution of 0.52 and 1.94. Morphology of derivatives differed structurally relative to native starch with FTIR spectra showing new peaks at 1735, 1435, 1370, and 1215 cm ⁻¹ , indicating successful esterification reactions. Furthermore, x‐ray diffraction showed a shift of the typical B‐type crystallinity toward amorphism with increasing degree of acetylation. Thermogravimetric analysis revealed the dual‐modified starch with acetyl DS of 1.94 as the most thermally stable with thermal degradation temperature of 325°C, while differential scanning calorimetry (DSC) revealed it as the only derivative with glass transition temperature (152.5°C). Pasting properties were recorded to change significantly with increasing degree of acetylation, with the dual‐modified starch with high degree of acetylation exhibiting a complete loss of pasting behavior. These findings demonstrate that esterification reactions could impart distinct functionalities to potato residues which could be further utilized for tailored applications in biobased material development.

Despite the potential of mycelium-based biomaterials as renewable alternatives to synthetic materials in the biomedical, construction, fashion, and packaging industries, their translation into scalable applications is hindered by reliance on a limited number of species, resource-intensive cultivation, and poorly understood substrate–property dynamics. Thus, we systematically screened various fungal isolates, resulting in the identification of seven non-pathogenic species with strong potential as biomaterials, viz., Absidia koreana , Achaetomium globosum , Cubamyces lactineus , Hypoxylon sp., Mucor fragilis , Periconia macrospinosa , and Xylaria berteroi . Subsequently, the fungi were cultivated on agro-residues and various commercial media to assess the effects of growth substrates on mycelial development and material properties. Quantitative analyses revealed that wheat bran agar (WBA) media competed favourably with Sabouraud dextrose agar (SDA), promoting denser, more cohesive mycelial networks despite their lower refinement and lower cost. Fourier transform infrared spectroscopy revealed distinct modulation of polysaccharide-, protein-, and chitin-associated functional groups, suggesting substrate-driven biochemical remodelling across different mycelia, while scanning electron microscopy showed enhanced hyphal interconnectivity, surface roughness, and microstructural heterogeneity in mycelia produced on agro-residues. Notably, A. koreana was identified as the most promising of all the evaluated fungi based on biomass productivity and thermal resistance (295 °C), as well as its smooth, branched, and thick hyphae network with the highest average diameter (5.02 ± 0.38 µm on SDA and 6.99 ± 0.53 µm on WBA). The dynamic mechanical analysis highlighted the effect of the growing substrates on the mechanical performance of the derived mycelium sheet, with the highest ultimate stress of 15.54 MPa, maximum storage modulus of 2109 MPa, and the maximum loss modulus of 107.9 MPa for X. berteroi on SDA, the highest storage modulus at lower temperature of 1332 MPa for P. macrospinosa on SDA, while the highest damping behaviour at lower temperature (45 °C) of 0.115 for Hypoxylon sp., and the maximum damping behaviour of 0.451 for X. berteroi on WBA. Finally, elemental analysis of agro-residues indicates their reusability for sustainable fungal cultivation in biotechnological industries. Collectively, these findings demonstrate that agro-residues are not merely viable substitutes for commercial media but represent superior platforms for tailoring mycelium material properties. Key points: • Improvement of fungal growth structure and protein content on agro-waste relative to commercial media. • Thermal stability of Absidia koreana mycelium, a top biomaterial candidate. • Compositional analysis indicates the reusability of agro-wastes as growth substrates.

Fish-based collagen supplements have potential health benefits, including antioxidant, ACE inhibitory, and DPP-IV inhibitory properties, which are expressed upon their digestion in the gastrointestinal system, thus releasing bioactive peptides (BPs). This study evaluated the pre-digestion of fish collagen using papain as a pre-digestive enzyme, which has broad specificity to enhance collagen breakdown and BPs release. Fish skin collagen was extracted via acid solubilisation, confirmed as type-I, and subsequently hydrolysed using two methods: pepsin-trypsin digestion (PTD) and pre-digestion with papain followed by PTD (PDPTD). The PDPTD–fish collagen hydrolysates (FCH) exhibited IC50 values (mg/mL) of 0.088 for ACE, 1.67 for DPP-IV, as well as 2.38 and 0.026 for antioxidant activities including DPPH and ABTS radicals scavenging, respectively, which were significantly lower than that of PTD-FCH. The FCH (PTD and PDPTD) were identified using LC-MS/MS analysis, and molecular docking studies showed lower binding energies for PDPTD–FCH peptides, particularly IGFPGFPG, against ACE (-11.2 kcal/mol) and DPP-IV (-9.1 kcal/mol), suggesting better inhibitory ability exhibited by BPs. This study highlighted fish collagen as a valuable source of BPs with enhanced bioactivity when pre-digested with papain, indicating its potential for functional foods and nutraceutical industries. Graphical Abstract

Ten phyllospheric yeast strains were studied for their potential as biocontrol agents against fruit spoilage mould. The efficacy of these yeasts against Botrytis cinerea and Fusarium fujikuroi was assessed using dual-culture, mouth-to-mouth, radial growth inhibition and post-harvest fruit assays. Additionally, their capacity for producing hydrolytic enzymes was examined. Results from the ten yeasts revealed dual culture antagonism ranging from 41% to 63% against B. cinerea and 23% to 48% against F. fujikuroi, along with radial inhibition ranging from 70% to 100% and 47% to 100%, respectively. Additionally, in vitro inhibition through the production of volatile organic compounds (VOCs) varied from 2% to 46% against B. cinerea and 6% to 64% against F. fujikuroi. Overall, Aureobasidium melanogenum J7, Suhomyces pyralidae Y1117, Dekkera anomala V38, and Rhodotorula diarenensis J43 emerged as the best-performing biocontrol yeasts. Volatile organic compounds produced by the four yeasts were also identified and included in fruit bioassays using pears and tomatoes. Various VOCs, including 1-butanol, 3-methylbutanol, and butyric acid, were linked to the antagonistic properties of the selected yeasts. Lastly, the four chosen yeast strains significantly mitigated post-harvest spoilage caused by B. cinerea and F. fujikuroi in pear and tomato fruits, with D. anomala V38 exhibiting the greatest inhibitory activity. These findings underscore a potential sustainable and efficient approach to reducing mould-induced post-harvest spoilage while reducing reliance on synthetic fungicides.

Background: Different parts of Allanblackia floribunda, Calotropis procera, Hymenocardia acida, Irvingia gabonensis, Newbouldia laevis, and Xylopia acutiflora have been used traditionally across different parts of Cameroon to overcome infectious diseases, especially pneumonia. Hence, this study investigated the antibacterial potential of six Cameroonian medicinal plants against selected ESKAPE pathogens (Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa) as well as Streptococcus pneumoniae. Methodology: The inhibitory activities of different extracts from six Cameroonian plants against the pathogens were evaluated by determining their MICs. Subsequently, the top four bioactive plant extracts were assessed for antibiofilm activity, time-kill kinetics, cytotoxicity (Raw and Vero cell lines), as well as antioxidant activities. Finally, the effect of the most potent extract, viz. ethanolic extract of Xylopia acutiflora steam bark, on bacterial morphology was elucidated through scanning electron microscopy while its phytochemical composition was profiled using liquid chromatography–mass spectrometry (LC–MS). Results: Twenty-two out of the 32 prepared extracts showed significant antibacterial activity, with MICs varying from 31.5 to 1000 µg/mL. The ethanolic, methanolic, and hydroethanolic extracts from Xylopia acutifolia and ethanolic extract from Colotropix procera exhibited broad-spectrum activity, inhibiting and eradicating bacterial biofilm. Furthermore, the extract from X. acutifolia was shown to be the most effective scavenger against DPPH (IC₅₀; 83.79 ± 1.92 µg/mL) and FRAP (IC₅₀; 22.89 ± 1.36 µg/mL) radicals, while C. procera extract was the most effective against ABTS (IC₅₀; 67.95 ± 1.83 µg/mL). The extracts were demonstrated to possess low cytotoxicity on both Raw and Vero cell lines. In addition, SEM revealed that X. acutifolia elicited cell membrane rupture and consequently cytoplasm leakage in E. coli and P. aeruginosa. Twenty-four different compounds were detected in the X. acutifolia extract via LC–MS analysis, and it was hypothesized that the recorded bioactivity in the extract might be ascribed to these compounds. Conclusion: Results from this study have scientifically validated the ethnomedicinal uses of the six Cameroonian plants as therapeutics for infections with X. acutiflora ethanolic extract displaying the highest bioactivity. Thus, there is the need for further investigations into phytochemicals from these plants as they could serve as important sources of novel antioxidants and antimicrobial agents. Graphical