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(11)
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.