Oscillospira is a class of organism that often appears in high-throughput sequencing data but has not been purely cultured and is widely present in the animal and human intestines. There is a strong association between variation in Oscillospira abundance and obesity, leanness, and human health. In addition, a growing body of studies has shown that Oscillospira is also implicated in other diseases, such as gallstones and chronic constipation, and has shown some correlation with the positive or negative changes in its course. Sequencing data combined with metabolic profiling indicate that Oscillospira is likely to be a genus capable of producing short-chain fatty acids (SCFAs) such as butyrate, which is an important reference indicator for screening “next-generation probiotics “. Considering the positive effects of Oscillospira in some specific diseases, such as obesity-related metabolic diseases, it has already been characterized as one of the next-generation probiotic candidates and therefore has great potential for development and application in the future food, health care, and biopharmaceutical products.

Yarrowia lipolytica is categorized as a generally recognized as safe (GRAS) organism and is a heavily documented, unconventional yeast that has been widely incorporated into multiple industrial fields to produce valuable biochemicals. This study describes the construction of a CRISPR-Cas9 system for genome editing in Y. lipolytica using a single plasmid (pCAS1yl or pCAS2yl) to transport Cas9 and relevant guide RNA expression cassettes, with or without donor DNA, to target genes. Two Cas9 target genes, TRP1 and PEX10, were repaired by non-homologous end-joining (NHEJ) or homologous recombination, with maximal efficiencies in Y. lipolytica of 85.6 % for the wild-type strain and 94.1 % for the ku70/ku80 double-deficient strain, within 4 days. Simultaneous double and triple multigene editing was achieved with pCAS1yl by NHEJ, with efficiencies of 36.7 or 19.3 %, respectively, and the pCASyl system was successfully expanded to different Y. lipolytica breeding strains. This timesaving method will enable and improve synthetic biology, metabolic engineering and functional genomic studies of Y. lipolytica.

The red yeast Rhodosporidium toruloides naturally produces microbial lipids and carotenoids. In the past decade or so, many studies demonstrated R. toruloides as a promising platform for lipid production owing to its diverse substrate appetites, robust stress resistance and other favorable features. Also, significant progresses have been made in genome sequencing, multi-omic analysis and genome-scale modeling, thus illuminating the molecular basis behind its physiology, metabolism and response to environmental stresses. At the same time, genetic parts and tools are continuously being developed to manipulate this distinctive organism. Engineered R. toruloides strains are emerging for enhanced production of conventional lipids, functional lipids as well as other interesting metabolites. This review updates those progresses and highlights future directions for advanced biotechnological applications.

Butanol is an industrial commodity and also considered to be a more promising gasoline substitute compared to ethanol. Renewed attention has been paid to solvents (acetone, butanol and ethanol) production from the renewable and inexpensive substrates, for example, lignocellulose, on account of the depletion of oil resources, increasing gasoline prices and deteriorating environment. Limited to current tools for genetic manipulation, it is difficult to develop a genetically engineered microorganism with combined ability of lignocellulose utilization and solvents production. Mixed culture of cellulolytic microorganisms and solventogenic bacteria provides a more convenient and feasible approach for ABE fermentation due to the potential for synergistic utilization of the metabolic pathways of two organisms. But few bacteria pairs succeeded in producing biobutanol of high titer or high productivity without adding butyrate. The aim of this work was to use Clostridium cellulovorans 743B to saccharify lignocellulose and produce butyric acid, instead of adding cellulase and butyric acid to the medium, so that the soluble sugars and butyric acid generated can be subsequently utilized by Clostridium beijerinckii NCIMB 8052 to produce butanol in one pot reaction.