The present invention generally relates to methods of biological reduction of metal-cyanide complexes after metal-cyanidation and methods of biologically hydrolysing cyanide. More particularly, the present invention allows the engineering of an integrated synthetic lixiviant biological system to be housed within a synthetic host (such as the cyanogenic Chromobacterium violaceum) for efficient precious metal recovery and toxic metal remediation of electronic waste; with up to four main components/modules in the design and engineering of the synthetic host: 1) synthetic cyanogenesis; 2) synthetic metal recovery; 3) synthetic cyanolysis; and 4) synthetic circuits for lixiviant biology. Bacteria capable of reducing ionic metal to ionic metal (such as gold or silver) as nanoparticles, comprising mercury(ll) reductase (MerA) comprising a substitution mutation at position V317, Y441, C464, A323D, A414E, G415I, E416C, L417I, I418D, or A422N, are also disclosed. Processes of synthetic cyanide lixiviant production using genetically engineered bacterium transformed with a heterologous hydrogen cyanide synthase gene and a heterologous 3-phosphoglycerate dehydrogenase mutant gene are also disclosed. Processes of synthetic cyanolysis using a genetically engineered bacterium transformed with a heterologous nitrilase gene are also disclosed.

The present disclosure provides for genetically modified organisms that provide numerous health benefits but also have an improved flavor profile and a more palatable aroma for the consumer of the organism.

The disclosure relates to mutant gene(s) that confer upon microorganisms that express them an improved capacity to utilize xylose and improved capacity to co-utilize glucose and xylose thereby resulting in improved growth of the microorganism. Further encompassed are methods of producing fatty acids and fatty acid derivatives from cellulosic biomass, xylose, and/or a glucose/xylose mix by employing the host cells expressing the engineered XylR variants and compositions of biologically produced fatty acids and fatty acid derivatives.

The disclosure discloses preparation of an L-amino acid deaminase mutant and application thereof, belonging to the technical field of gene engineering. Through pmirLAAD protein modification, analysis of a flexible loop structure around a binding site of the pmirLAAD product, and design of the best mutant, the modification method of the disclosure overcomes the defect that the catalytic efficiency of the previous wild-type enzyme is reduced due to product inhibition, and is tested by experiments. Compared with the control, the catalytic efficiency (1.61 mM.sup.−1.Math.min.sup.−1) and the product inhibition constant (5.4 mM) of the finally obtained best mutant pmirLAAD.sup.M4 are respectively increased by 5.2 times and 5.7 times. The yield of α-ketoisovaleric acid can reach 96.5 g/L, and the transformation rate is greater than 97%. By adopting the method of the disclosure, the cost can be greatly reduced, and the industrialization process of production of α-ketoisovaleric acid by an enzymatic transformation method is accelerated.

The present invention describes methods to produce a synthetic or semi-synthetic cysteine synthase/PLP-dependent decarboxylase (sCs/PLP-DC). More particularly, the invention relates to genetic modification of organisms including eukaryotes and prokaryotes to express a functional sCs/PLP-DC. The invention includes methods to produce taurine in organisms that contain native or heterologous (transgenic) taurine biosynthetic pathways or cells that have taurine by enrichment. The invention also relates to methods to increase taurine levels in the cells and to use the said cells or extracts or purifications from the cells that contain the invention to produce plant growth enhancers, food, animal feed, aquafeed, food or drink supplements, animal-feed supplements, dietary supplements, health supplements or taurine.

The disclosure relates to recombinant microorganisms for the production of fatty amines and derivatives thereof. Further contemplated are cultured recombinant host cells as well as methods of producing fatty amines by employing these host cells.

The invention relates to the use of genetic constructs, expression cassettes and recombinant vectors comprising such constructs and cassettes for gene therapy and methods for treating neurodegenerative disorders, such as Parkinson's disease (PD). The constructs comprise a promoter operably linked to a first coding sequence, which encodes tyrosine hydroxylase (TH), and a second coding sequence, which encodes GTP cyclohydrolase 1 (GCH1). The second coding sequence is 3′ to the first coding sequence, and the first and second coding sequences are part of a single operon, wherein the genetic construct does not encode aromatic amino acid decarboxylase (AADC). The construct is delivered to the cerebrospinal fluid (CSF) of the subject.

The present invention discloses an amino acid dehydrogenase mutant and application thereof in synthesizing L-glufosinate-ammonium, the amino acid dehydrogenase mutant is obtained by a single mutation or a multi-site mutation of the amino acid at position 95, 108, 172, 303 of the amino acid sequence shown in SEQ ID No. 2. The amino acid dehydrogenase mutant DyGDH-F95I-A108T-R172P-R303H prepared by the present invention has a specific enzyme activity that is 33 times higher than that of the original Aldo-keto reductase, and the concentration of the largest substrate, 2-carbonyl-4-(hydroxymethylphosphinyl)-butyric acid reaches 500 mM, the amino acid dehydrogenase mutant has more industrial application prospects. Using the amino acid dehydrogenase mutant to produce L-glufosinate-ammonium, the reaction time is significantly shortened, the general process takes 20 hours, and the reaction time of the present invention only requires 120 minutes, which shows that the amino acid dehydrogenase mutant has a good industrial application prospect.

The disclosure discloses preparation of an L-amino acid deaminase mutant and application thereof, belonging to the technical field of gene engineering. Through pmirLAAD protein modification, analysis of a flexible loop structure around a binding site of the pmirLAAD product, and design of the best mutant, the modification method of the disclosure overcomes the defect that the catalytic efficiency of the previous wild-type enzyme is reduced due to product inhibition, and is tested by experiments. Compared with the control, the catalytic efficiency (1.61 mM.sup.−.Math.min.sup.−1) and the product inhibition constant (5.4 mM) of the finally obtained best mutant pmirLAAD.sup.M4 are respectively increased by 5.2 times and 5.7 times. The yield of α-ketoisovaleric acid can reach 96.5 g/L, and the transformation rate is greater than 97%. By adopting the method of the disclosure, the cost can be greatly reduced, and the industrialization process of production of α-ketoisovaleric acid by an enzymatic transformation method is accelerated.

Methods for recombinant and enzymatic production of mogroside compounds and compositions containing mogroside compounds are provided by this invention.