Flavonoids are polyphenols that are important organic chemicals in plants. The health benefits of flavonoids that result in high commercial values make them attractive targets for large-scale production through bioengineering. Strategies such as engineering a flavonoid biosynthetic pathway in microbial hosts provide an alternative way to produce these beneficial compounds. Escherichia coli, Saccharomyces cerevisiae and Streptomyces sp. are among the expression systems used to produce recombinant products, as well as for the production of flavonoid compounds through various bioengineering approaches including clustered regularly interspaced short palindromic repeats (CRISPR)-based genome engineering and genetically encoded biosensors to detect flavonoid biosynthesis. In this study, we review the recent advances in engineering model microbial hosts as being the factory to produce targeted flavonoid compounds.

Surfactin is a biological surfactant with numerous potential applications. In this study, Bacillus subtilis was engineered to improve surfactin production by the activation of two competence-stimulating pheromones, ComX and competence and sporulation factor (CSF) to stimulate the transcription of srfA operon. Both signaling factors, encoded by comX and phrC, were successfully overexpressed and subsequently increased surfactin production. Surfactin produced by engineered strains showed functional groups similar to the commercially available surfactin analyzed via Fourier transform infrared spectroscopy (FTIR). Surfactin production in the B. subtilis (pHT43-comXphrC) strain was 6.4-fold greater than in the wild strain, with approximately 135.1 mg/L surfactin produced after 48 h cultivation. To reduce the production costs of surfactin, synthetic wastewater was used, from which the B. subtilis (pHT43-comXphrC) strain produced approximately 140.2 mg/L surfactin. The results obtained demonstrated the production of surfactin from synthetic wastewater, which is beneficial in lowering the overall production costs.

Oral squamous cell carcinoma is associated with many known risk factors including tobacco smoking, chronic alcoholism, poor oral hygiene, unhealthy dietary habits and microbial infection. Previous studies have highlighted Candida albicans host tissue infection as a risk factor in the initiation and progression of oral cancer. C albicans How to cite this article: Engku Nasrullah Satiman EAF, Ahmad H, Ramzi AB, et al. The role of Candida albicans candidalysin ECE1 gene in oral carcinogenesis.

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BackgroundG. boninense is a hemibiotrophic fungus that infects oil palms (Elaeis guineensis Jacq.) causing basal stem rot (BSR) disease and consequent massive economic losses to the oil palm industry. The pathogenicity of this white-rot fungus has been associated with cell wall degrading enzymes (CWDEs) released during saprophytic and necrotrophic stage of infection of the oil palm host. However, there is a lack of information available on the essentiality of CWDEs in wood-decaying process and pathogenesis of this oil palm pathogen especially at molecular and genome levels.MethodsIn this study, comparative genome analysis was carried out using the G. boninense NJ3 genome to identify and characterize carbohydrate-active enzyme (CAZymes) including CWDE in the fungal genome. Augustus pipeline was employed for gene identification in G. boninense NJ3 and the produced protein sequences were analyzed via dbCAN pipeline and PhiBase 4.5 database annotation for CAZymes and plant-host interaction (PHI) gene analysis, respectively. Comparison of CAZymes from G. boninense NJ3 was made against G. lucidum, a well-studied model Ganoderma sp. and five selected pathogenic fungi for CAZymes characterization. Functional annotation of PHI genes was carried out using Web Gene Ontology Annotation Plot (WEGO) and was used for selecting candidate PHI genes related to cell wall degradation of G. boninense NJ3.ResultsG. boninense was enriched with CAZymes and CWDEs in a similar fashion to G. lucidum that corroborate with the lignocellulolytic abilities of both closely-related fungal strains. The role of polysaccharide and cell wall degrading enzymes in the hemibiotrophic mode of infection of G. boninense was investigated by analyzing the fungal CAZymes with necrotrophic Armillaria solidipes, A. mellea, biotrophic Ustilago maydis, Melampsora larici-populina and hemibiotrophic Moniliophthora perniciosa. Profiles of the selected pathogenic fungi demonstrated that necrotizing pathogens including G. boninense NJ3 exhibited an extensive set of CAZymes as compared to the more CAZymes-limited biotrophic pathogens. Following PHI analysis, several candidate genes including polygalacturonase, endo β-1,3-xylanase, β-glucanase and laccase were identified as potential CWDEs that contribute to the plant host interaction and pathogenesis.DiscussionThis study employed bioinformatics tools for providing a greater understanding of the biological mechanisms underlying the production of CAZymes in G. boninense NJ3. Identification and profiling of the fungal polysaccharide- and lignocellulosic-degrading enzymes would further facilitate in elucidating the infection mechanisms through the production of CWDEs by G. boninense. Identification of CAZymes and CWDE-related PHI genes in G. boninense would serve as the basis for functional studies of genes associated with the fungal virulence and pathogenicity using systems biology and genetic engineering approaches.

Triacylglycerol (TAG) is a microbial oil feedstock for biodiesel production that uses an inexpensive substrate, such as glycerol. Here, we demonstrated the overproduction of TAG from glycerol in engineered Saccharomyces cerevisiae via the glycerol-3-phosphate (G3P) pathway by overexpressing the major TAG synthesis. The G3P accumulation was increased 2.4-fold with the increased glycerol utilization gained by the overexpression of glycerol kinase (GUT1). By overexpressing diacylglycerol acyltransferase (DGA1) and phospholipid diacylglycerol acyltransferase (LRO1), the engineered YPH499 (pGutDgaLro1) strain produced 23.0 mg/L lipids, whereas the YPH499 (pESC-TRP) strain produced 6.2 mg/L total lipids and showed a lipid content that was increased 1.4-fold compared with 3.6% for the wild-type strain after 96 h of cultivation. After 96 h of cultivation using glycerol, the overall content of TAG in the engineered strain, YPH499 (pGutDgaLro1), yielded 8.2% TAG, representing a 2.3-fold improvement, compared with 3.6% for the wild-type strain. The results should allow a reduction of costs and a more sustainable production of biodiesel.

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