The rapidly growing demand for energy and the environmental concerns about carbon dioxide emissions make the development of renewable biofuels more and more attractive. Tremendous academic and industrial efforts have been made to produce bioethanol, which is one major type of biofuel. The current production of bioethanol is limited for commercialization because of issues with food competition (from food-based biomass) or cost effectiveness (from lignocellulose-based biomass). In this report we applied a consolidated bioprocessing strategy to integrate photosynthetic biomass production and microbial conversion producing ethanol together into the photosynthetic bacterium, Synechocystis sp. PCC6803, which can directly convert carbon dioxide to ethanol in one single biological system. A Synechocystis sp. PCC6803 mutant strain with significantly higher ethanol-producing efficiency (5.50 g L⁻¹, 212 mg L⁻¹ day⁻¹) compared to previous research was constructed by genetically introducing pyruvate decarboxylase from Zymomonas mobilis and overexpressing endogenous alcohol dehydrogenase through homologous recombination at two different sites of the chromosome, and disrupting the biosynthetic pathway of poly-β-hydroxybutyrate. In total, nine alcohol dehydrogenases from different cyanobacterial strains were cloned and expressed in E. coli to test ethanol-producing efficiency. The effects of different culturing conditions including tap water, metal ions, and anoxic aeration on ethanol production were evaluated.

The enhanced ethylene production (9.7 mL L⁻¹h⁻¹) was achieved by genetic modifications and improved cultivation ofSynechocystissp. PCC 6803.

L-glutamate family amino acids (GFAAs), consisting of l-glutamate, l-arginine, l-citrulline, l-ornithine, l-proline, l-hydroxyproline, γ-aminobutyric acid, and 5-aminolevulinic acid, are widely applied in the food, pharmaceutical, cosmetic, and animal feed industries, accounting for billions of dollars of market activity. These GFAAs have many functions, including being protein constituents, maintaining the urea cycle, and providing precursors for the biosynthesis of pharmaceuticals. Currently, the production of GFAAs mainly depends on microbial fermentation using Corynebacterium glutamicum (including its related subspecies Corynebacterium crenatum), which is substantially engineered through multistep metabolic engineering strategies. This review systematically summarizes recent advances in the metabolic pathways, regulatory mechanisms, and metabolic engineering strategies for GFAA accumulation in C. glutamicum and C. crenatum, which provides insights into the recent progress in l-glutamate-derived chemical production.

Background: RNA-sequencing (RNA-seq) has been widely used to study the dynamic expression patterns of transcribed genes, which can lead to new biological insights. However, processing and analyzing these huge amounts of histological data remains a great challenge for wet labs and field researchers who lack bioinformatics experience and computational resources. Results: We present BarleyExpDB, an easy-to-operate, free, and web-accessible database that integrates transcriptional profiles of barley at different growth and developmental stages, tissues, and stress conditions, as well as differential expression of mutants and populations to build a platform for barley expression and visualization. The expression of a gene of interest can be easily queried by searching by known gene ID or sequence similarity. Expression data can be displayed as a heat map, along with functional descriptions as well as Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Proteins Families Database, and Simple Modular Architecture Research Tool annotations. Conclusions: BarleyExpDB will serve as a valuable resource for the barley research community to leverage the vast publicly available RNA-seq datasets for functional genomics research and crop molecular breeding.