A method for producing isoprene includes culturing E. coli, which has isoprene productivity and in which a gene encoding a recA protein is attenuated or deleted, in a medium containing a carbon source. Therefore, a great amount of isoprene may be produced within a short period of time, and thereby considerably decreasing isoprene production unit costs.

The present disclosure provides compositions and methods for rapid production of chemicals in genetically engineered microorganisms in a large scale. Also provided herein is a high-throughput metabolic engineering platform enabling the rapid optimization of microbial production strains. The platform, which bridges a gap between current in vivo and in vitro bio-production approaches, relies on dynamic minimization of the active metabolic network.

The present invention relates to a microorganism genetically modified for production of ectoine, wherein said microorganism comprises the following modifications: expression of a heterologous gene ectA encoding a diaminobutyric acid acetyltransferase having at least 90% similarity with SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4 or SEQ ID NO: 5, a heterologous gene ectB encoding a diaminobutyric acid aminotransferase having at least 90% similarity with SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9 or SEQ ID NO: 10, a heterologous gene ectC encoding an ectoine synthase having at least 90% similarity with SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14 or SEQ ID NO: 15 and deletion of pykA and pykF genes. The present invention also relates to a method for the production of ectoine using said microorganism.

The invention provides a method for producing a terpene or a precursor thereof by microbial fermentation. Typically, the method involves culturing a recombinant bacterium in the presence of a gaseous substrate whereby the bacterium produces a terpene or a precursor thereof, such as mevalonic acid, isopentenyl pyrophosphate, dimethylallyl pyrophosphate, isoprene, geranyl pyrophosphate, farnesyl pyrophosphate, and/or farnesene. The bacterium may comprise one or more exogenous enzymes, such as enzymes in mevalonate, DXS, or terpene biosynthesis pathways.

The present disclosure provides CasX proteins, nucleic acids encoding the CasX proteins, and modified host cells comprising the CasX proteins and/or nucleic acids encoding same. CasX proteins are useful in a variety of applications, which are provided. The present disclosure provides CasX guide RNAs that bind to and provide sequence specificity to the CasX proteins, nucleic acids encoding the CasX guide RNAs, and modified host cells comprising the CasX guide RNAs and/or nucleic acids encoding same. CasX guide RNAs are useful in a variety of applications, which are provided. The present disclosure provides archaeal Cas9 polypeptides and nucleic acids encoding same, as well as their associated archaeal Cas9 guide RNAs and nucleic acids encoding same.

Multi-carbon compounds such as ethanol, n-butanol, sec-butanol, isobutanol, tert-butanol, fatty (or aliphatic long chain) alcohols, fatty acid methyl esters, 2,3-butanediol and the like, are important industrial commodity chemicals with a variety of applications. The present invention provides metabolically engineered host microorganisms which metabolize methane (CH.sub.4) as their sole carbon source to produce multi-carbon compounds for use in fuels (e.g., bio-fuel, bio-diesel) and bio-based chemicals. Furthermore, use of the metabolically engineered host microorganisms of the invention (which utilize methane as the sole carbon source) mitigate current industry practices and methods of producing multi-carbon compounds from petroleum or petroleum-derived feedstocks, and ameliorate much of the ongoing depletion of arable food source “farmland” currently being diverted to grow bio-fuel feedstocks, and as such, improve the environmental footprint of future bio-fuel, bio-diesel and bio-based chemical compositions.

The disclosure discloses a genetically engineered strain for sarcosine production as well as a construction method and application. The genetically engineered strain is obtained by using Escherichia coli as a host and by integrating a single copy of imine reductase gene dpkA on its genome; singly copying citrate synthase gene gltA; knocking out glyoxylate cycle inhibitor gene iclR; knocking out malate synthase gene aceB; integrating a single copy of isocitrate lyase gene aceA; integrating a single copy of membrane-bound transhydrogenase gene pntAB; knocking out 2-ketate reductase gene ycdW; integrating a single copy of phosphoenolpyruvate carboxylase gene ppc; and knocking out pyruvate kinase gene pykF. After system metabolism transformation, the engineered strain can synthesize sarcosine with glucose and methylamine as main raw materials. The sarcosine titer can reach 10 g/L after fermentation for 30 h in a 5 L fermenter.

The biological production of beta-hydroxyisovalerate (βHIV) using at least one non-natural enzyme. The non-natural enzyme for the biologically-derived βHIV provides more beta-hydroxyisovalerate synthase activity than the wild-type parent. The non-natural enzyme having one or more modifications of substrate-specificity positions. The non-natural enzyme can be expressed in a microorganism, such as a yeast or bacteria, wherein the microorganism comprises an active βHIV metabolic pathway for the production of βHIV. Alternatively, the non-natural enzyme can be a βHIV synthase used to produce βHIV in a cell-free environment. The biological derivation of βHIV eliminates toxic by-products and impurities that result from the chemical production of βHIV, such that βHIV produced by a non-natural enzyme prior to any isolation or purification process has not been in substantial contact with any halogen-containing component.

The invention provides a method for producing a terpene or a precursor thereof by microbial fermentation. Typically, the method involves culturing a recombinant bacterium in the presence of a gaseous substrate whereby the bacterium produces a terpene or a precursor thereof, such as mevalonic acid, isopentenyl pyrophosphate, dimethylallyl pyrophosphate, isoprene, geranyl pyrophosphate, farnesyl pyrophosphate, and/or farnesene. The bacterium may comprise one or more exogenous enzymes, such as enzymes in mevalonate, DXS, or terpene biosynthesis pathways.

The present disclosure provides compositions and methods for rapid production of chemicals in genetically engineered microorganisms in a large scale. Also provided herein is a high-throughput metabolic engineering platform enabling the rapid optimization of microbial production strains. The platform, which bridges a gap between current in vivo and in vitro bio-production approaches, relies on dynamic minimization of the active metabolic network.