The invention provides an assay for identifying a bacterium capable of binding elemental heavy metal, comprising the following steps: cultivating a test bacterium in a suitable first culture medium; immersing at least a surface portion of a test tool into the first culture medium for a second predetermined period of time, said surface portion being coated by elemental heavy metal, respectively; removing said test tool from said first culture medium and optionally rinsing the test tool; contacting a second culture medium with the surface portion coated by elemental heavy metal of said test tool removed in the previous step; and identifying the test bacterium as being capable of binding elemental heavy metal from growth of the test bacterium in said second culture medium.

The present invention relates to methods and systems of pitching yeast to fermentation reactors. More particularly, the present invention involves pitching yeast from one fermentation tank to at least one additional fermentation tank. Advantageously, yeast can be continuously pitched from fermentor to fermentor for as long as practically desirable.

The present invention relates to methods and systems of pitching yeast to fermentation reactors. More particularly, the present invention involves pitching yeast from one fermentation tank to at least one additional fermentation tank. Advantageously, yeast can be continuously pitched from fermentor to fermentor for as long as practically desirable.

The present invention concerns a process for producing enzymes by a strain belonging to a filamentous fungus, said process comprising two steps: (a) a first step of growing the fungi, in the presence of at least one carbon-based growth substrate, in a stirred and aerated bioreactor in batch phase, at a pH of not more than 4.6; (b) a second step of producing enzymes, starting from the culture medium obtained in the first step (a), in the presence of at least one inductive carbon-based substrate, at a pH of not more than 4.6.

The present invention concerns a process for producing enzymes by a strain belonging to a filamentous fungus, said process comprising two steps: (a) a first step of growing the fungi, in the presence of at least one carbon-based growth substrate, in a stirred and aerated bioreactor in batch phase, at a pH of not more than 4.6; (b) a second step of producing enzymes, starting from the culture medium obtained in the first step (a), in the presence of at least one inductive carbon-based substrate, at a pH of not more than 4.6.

Biocatalytic conversion systems and methods of producing and using same that have improved yields are disclosed. The systems and methods involve co-fermentation of sugars and gaseous substrates for alcohol, ketone, and/or organic acid production. The systems and methods may include biocatalytically converting at least one sugar substrate into at least one of alcohol, at least one ketone, and/or at least one organic acid. The systems and methods may further include biocatalytically converting gases that comprise CO.sub.2 and H.sub.2 to at least one alcohol and/or at least one organic acid, thereby adding extra revenue to biorefineries.

Biocatalytic conversion systems and methods of producing and using same that have improved yields are disclosed. The systems and methods involve co-fermentation of sugars and gaseous substrates for alcohol, ketone, and/or organic acid production. The systems and methods may include biocatalytically converting at least one sugar substrate into at least one of alcohol, at least one ketone, and/or at least one organic acid. The systems and methods may further include biocatalytically converting gases that comprise CO.sub.2 and H.sub.2 to at least one alcohol and/or at least one organic acid, thereby adding extra revenue to biorefineries.

Described herein are recombinant yeast cells expressing a xylulose kinase (XK) which are suitable for fermentation of pentoses. Also described are recombinant yeast cells with higher tolerance to formic and/or acetic acid and suitable for fermentation of pentoses. Also described are recombinant yeast cells expressing an enolase, a phosphofructokinase beta subunit, a 6-phosphofructo-2-kinase, a glucose-6-phosphate isomerase, a phosphoglycerate mutase and/or a triose-phosphate isomerase, and suitable for fermentation of pentoses. Also described are recombinant yeast cells expressing a a phosphoglucomutase and/or phosphoribomutase which are suitable for fermentation of pentoses. Further described are are methods of using or producing such recombinant yeast cells and related materials.

The present disclosure concerns recombinant yeast host cells having a first genetic modification for increasing formate production, when compared to a corresponding native yeast host cell as well as a source of formate dehydrogenase activity. The source of formate can be an internal source of formate dehydrogenase activity and/or the recombinant yeast host call can be supplemented by an external source of formate dehydrogenase activity.

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.