Fidelis Azi

Plant-derived oleanolic and ursolic acids are sought-after triterpenoid sapogenins used in modern curative and preventive medicines. Several plant species have been overexploited for triterpenoid sapogenin extraction. In this study, we reconfigured the metabolic fingerprints of Ganoderma lucidum and produced oleanolic and ursolic acids, ganoderic acids, and meroterpenoids. Oleanolic and ursolic acids were first synthesized in the medicinal mushroom by expressing amyrin-synthases and beta-amyrin 28-monooxygenase from plants. The production of sapogenin precursors (2,3-oxidosqualene) and ganoderic acid was enhanced by reconstructing the mushroom terpenoid biosynthetic pathway using a new terpenoid gene cluster recovered from the mycelium. Overexpression of the VeA–VelB velvet and LaeA proteins upregulated secondary metabolism and stimulated the hyperproduction of a renoprotective meroterpenoid. The VeA–VelB velvet and LaeA protein variants developed a radically distinctive yellow phenotype that has not yet been reported in any of the mushroom mycelial variants. CRISPR-AsCpf1-based lanosterol synthase editing repressed the competing ganoderic acid pathway and further enhanced 2,3-oxidosqualene accumulation and triterpenoid sapogenin biosynthesis. The oleanolic and ursolic acid titer reached 1.478 g L⁻¹ and 0.87 g L⁻¹, respectively, when the fermentation conditions were optimized in a 5 L lab bioreactor. This study presents fascinating metabolic engineering strategies that remodel Ganoderma's metabolic route and produce oleanolic acid, ursolic acid, ganoderic acids, and meroterpenoids. These new strains could replace wild plant species as a green source of triterpenoid sapogenins.

Cyanides are highly toxic chemicals in several edible plants that threaten food safety and human health. A phenotypically distinct Yarrowia lipolytica strain that efficiently detoxifies multiple cyanogenic glycosides from edible plants was constructed using a family 1 glycosyl-hydrolase (GH1). The strain displayed higher growth rates and metabolic activities when exposed to high concentrations of cyanides than the wild-type. It overexpressed genes that promoted the binding of molecular oxygen to the cytochrome iv complex. The engineered strain repressed fatty acid production to optimize energy production and activated the cyanide-resistant respiratory (AOX) pathway to circumvent HCN toxicity and maintain cellular homeostasis. It upregulated ribosome biogenesis, the sec-dependent protein export pathway, and the sulfur relay system to facilitate the production and transmembrane efflux of the secreted GH1 hydrolase. It efficiently degraded linamarin, amygdalin, prunasin, and dhurrin in food plants including cassava, germinated sorghum and Apricot seeds. The strain produced high phospholipids to support new membrane production and could be a cost-effective source of single-cell phospholipids. The findings demonstrate that the strain is a robust, sustainable, and potentially efficient strain that could be used for industrial bioconversion of plant materials containing glycosylated toxicants into safe foods and animal feeds.

Signal transduction is crucial for communication and cellular response in microbial communities. Consortia rely on it for effective communication, responding to changing environmental conditions, establishing community structures, and performing collective behaviors. Microbial signal transduction can be through quorum sensing (QS), two‐component signal transduction systems, biofilm formation, nutrient sensing, chemotaxis, horizontal gene transfer stress response, and so forth. The consortium uses small signaling molecules in QS to regulate gene expression and coordinate intercellular communication and behaviors. Biofilm formation allows cells to adhere and aggregate, promoting species interactions and environmental stress resistance. Chemotaxis enables directional movement toward or away from chemical gradients, promoting efficient resource utilization and community organization within the consortium. In recent years, synthetic microbial consortia have gained attention for their potential applications in biotechnology and bioremediation. Understanding signal transduction in natural and synthetic microbial consortia is important for gaining insights into community dynamics, evolution, and ecological function. It can provide strategies for biotechnological innovation for enhancing biosensors, biodegradation, bioenergy efficiency, and waste reduction. This review provides compelling insight that will advance our understanding of microbial signal transduction dynamics and its role in orchestrating microbial interactions, which facilitate coordination, cooperation, gene expression, resource allocation, and trigger specific responses that determine community success.

Fermented soybean products have attracted great attention due to their health benefits. In the present study, the hypoxia-injured PC12 cells induced by cobalt chloride (CoCl₂) were used to evaluate the neuroprotective potency of tofu fermented by Actinomucor elegans (FT). Results indicated that FT exhibited higher phenolic content and antioxidant activity than tofu. Moreover, most soybean isoflavone glycosides were hydrolyzed into their corresponding aglycones during fermentation. FT demonstrated a significant protective effect on PC12 cells against hypoxic injury by maintaining cell viability, reducing lactic dehydrogenase leakage, and inhibiting oxidative stress. The cell apoptosis was significantly attenuated by the FT through down-regulation of caspase-3, caspases-8, caspase-9, and Bax, and up-regulation of Bcl-2 and Bcl-xL. S-phase cell arrest was significantly inhibited by the FT through increasing cyclin A and decreasing the p21 protein level. Furthermore, treatment with the FT activated autophagy, indicating that autophagy possibly acted as a survival mechanism against CoCl₂-induced injury. Overall, FT offered a potential protective effect on nerve cells in vitro against hypoxic damage.

In the last decade, there have been an increase in safety concerns on the aflatoxins contents of cereals and cereal-derived food products in Nigeria. In the current study, evaluation of aflatoxins levels and molecular identification of toxigenic molds recovered from cereals and cereal-derived foods products in Nigeria were studied. Enzyme Link Immunosorbent Assay (ELISA) and high performance liquid chromatography (HPLC) methods were used for qualitative and quantitative aflatoxins evaluation, respectively. The result showed that aflatoxins were detected in 53 out of the 120 samples of the cereals and their products studied. The detected levels of aflatoxins in some of the samples were over the permissible (4 μg/kg) as recommended by relevant food regulatory authorities. Aflatoxins B1, B2, G1, and G2 were all detected in the sample, aflatoxin B1 was the most predominant in the samples. Aspergillus flavus (AZ19), was isolated and identified as the major contaminating mold. Thus, findings of this research provide strong evidence that incidence of aflatoxins contamination of food crops still remain a major problem in Nigeria agricultural sector. Key words: Aflatoxins, toxigenic molds, cereals, cereal-derived foods, Aspergillus flavus.

Summary: Water kefir microbiota was used to develop novel soy whey‐based beverages that have antioxidant activity. In the present study, comparative phenolics, antioxidant and metagenomic composition of the soy whey beverages fermented using three different water kefir microbiota, named WKFS‐A, WKFS‐B and WKFS‐C were investigated. WKFS‐B beverage had the highest concentrations of isoflavone aglycones (208.73 ± 2.78 mg L⁻¹) and phenolic acids (132.33 ± 3.41 mg L⁻¹) compared with WKFS‐A (193.88 ± 1.15 mg L⁻¹) and (91.73 ± 2.34 mg L⁻¹) and WKFS‐C (160.63 ± 1.76 mg L⁻¹) and (97.13 ± 2.63 mg L⁻¹), respectively. The WKFS‐B also showed higher DPPH and ABTS radical scavenging activity and ferric reducing antioxidant power compared with WKFS‐A and WKFS‐C beverages. Microbial species diversity index analysis showed that a higher concentration of isoflavone aglycones, phenolic acids and increased antioxidant activity in the WKFS‐B beverage correlates with the higher relative abundance of Lactobacillus genus. This study thus revealed that Lactobacillus dominated water kefir microbiota produces soy whey beverages with high phenolic acids, isoflavone aglycones and antioxidant activity.

In this study, heavy metal and microbial safety assessment of raw and cooked pumpkin and Amaranthus viridis leaves grown in Abakaliki, Nigeria, was examined. The levels of lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd), and mercury (Hg) were evaluated using atomic absorption spectrophotometer. The microbial cells were counted and further identified to species level using 16S rDNA and ITS rDNA sequencing analysis at CABI microbial identification services United Kingdom (UK). The results showed that the heavy metal concentrations of lead (10.5, 12.0), arsenic (7.5, 8.5), chromium (0.9, 0.1), and mercury (13.1, 14.0) in the pumpkin and A. viridis leaves, respectively, were above maximum acceptable limit according to relevant national and international food regulatory agencies (Tables and ). Cooking significantlyreduced the concentrations of the heavy metals at (p > 0.05) to or below, lead (6.8, 8.4), arsenic (5.1, 6.1), chromium (0.6.0.1), and mercury (9.5, 11.4) in the pumpkin and A. viridis leaves, respectively, but still not to international safe limit. The result of the microbial safety assessment showed that the microbial load of both the pumpkin and Amaranthus viridis leaves were above acceptable limit and the contaminating organisms were identified as Escherichia coli (504743), Klebsiella pneumonia (504744b), and Aspergillus flavus (504740).This study therefore shows that the vegetables (pumpkin and A. viridis leaves) contain unacceptable levels of toxic heavy metals and potentially dangerous pathogenic microorganisms, thus present significant health risk for the consumers.