The disclosure discloses recombinant Bacillus subtilis for synthesizing guanosine diphosphate fucose and a construction method and application thereof. The recombinant Bacillus subtilis is obtained by intensively expressing guanylate kinase and nucleotide diphosphokinase genes and expressing exogenous fucokinase and phosphate guanylyltransferase genes in a genome of Bacillus subtilis 168. According to the disclosure, a bacterial strain for synthesizing the guanosine diphosphate fucose is obtained by reconstructing the Bacillus subtilis 168, with a volume of intracellular accumulation up to 196.15 g/L. According to the disclosure, by intensively expressing the guanylate kinase and nucleotide diphosphokinase genes, and enhancing the supply of intracellular GDP-L-fucose composition cofactors, the synthesis of the guanosine diphosphate fucose is promoted. The construction method for the recombinant Bacillus subtilis of the disclosure is simple and convenient to use, thus having good application prospects.

An expression system and process for the production of Diphtheria toxin polypeptides or mutated forms thereof, such as the toxoid CRM197 polypeptide, in genetically-modified E. coli with high yield is described. The system and process is based on the uncoupling of biomass growth from recombinant protein induction, i.e. using an inducer of protein production that cannot be used as a carbon source for growth by the bacteria. The use of specific components and conditions that improve protein yields are also described.

The present invention provides a method for producing a fermentation product by culturing recombinant exosporium-producing Bacillus cells that express a fusion protein of interest on the exosporium in a medium containing sources of carbon and nitrogen in a total concentration of at least 20 g/L, resulting in a fermentation broth containing a high titer of the recombinant Bacillus spores.

A system for generating and using an assay key comprising growth conditions for a set of microorganisms for a set of diverse QAC-based culture media under a variety of incubation conditions known to modulate the effect of QAC on growth of some microorganisms in the set. Each culture medium is characterized by a pH and includes one or more QACs and one or more growth supplements. The set of culture media includes media comprising various combinations of pH, QAC type, QAC concentration, growth supplement type, and growth supplement concentration. The assay key can be used to identify a microorganism by inoculating a variety of growth media within the key and incubating the inoculated media under conditions within the key and comparing the resulting pattern of microorganism growth across the media and conditions with growth patterns for various known microorganisms across the media and conditions that are within the key.

The invention discloses a fermentation method for production of fucoxanthin by Nitzschia laevis, including the following steps of: step A, preparation of inocula; step B, fermentation culture: inoculating of Nitzschia laevis according to a certain volume ratio to reaction kettle containing sterile fermentation medium for aeration fermentation, preparing fucoxanthin fermentation broth through culture mean of fed-batch nutrient components; step C, obtaining high fucoxanthin induction culture solution by aeration induction culture under irradiation of monochromatic light or mixed light; extracting fucoxanthin from high fucoxanthin induction culture solution. The invention optimized fermentation condition by fed-batch nutrient components during aeration culture of alga Nitzschia laevis, thereby significantly increasing the cell density of Nitzschia laevis in sterile fermentation broth, and then treating high density fucoxanthin induction culture solution of Nitzschia laevis by using light treatment, inducing the accumulation of fucoxanthin, thereby further increasing productivity of fucoxanthin produced by fermentation.

This application provides a method for culturing Lactobacillus plantarum, which comprises culturing Lactobacillus plantarum in a medium comprising molasses, a yeast extract and sucrose at a temperature from 32° C. to 37° C.

The present invention provides a culture medium for inducing an increase in a plasmid copy number and use thereof. The culture medium for inducing an increase in a plasmid copy number of the present invention has a plasmid extraction concentration increased by from 45 to 95% compared with a conventional method for inducing a plasmid copy number, and has a plasmid extraction concentration increased by from 110 to 440% compared with an induction method using a culture medium without glucose and arabinose. The culture medium plays an important role in inducing an increase in a plasmid copy number and achieving high-throughput production.

Provided is a method for producing 2-pyrone-4,6-dicarboxylic acid (PDC) by culturing a microorganism that produces PDC. The present invention provides a method of producing PDC by culturing a microorganism that produces 2-pyrone-4,6-dicarboxylic acid (PDC), wherein the method comprises: dissolving the starting substance for production of PDC in a buffer solution that contains no alkali metals, and adjusting the pH of a culture solution with a buffer solution that contains no alkali metals.

An application of MAL33 gene deletion in improving the tolerance of Saccharomyces cerevisiae to inhibitors in a lignocellulose hydrolyzate is provided. The tolerance of the present MAL33 gene-deleted Saccharomyces cerevisiae strain to acetic acid is greatly improved, and the tolerance of the Saccharomyces cerevisiae strain to other typical inhibitors and H.sub.2O.sub.2 in the lignocellulose hydrolyzate is also improved. The lag period of the Saccharomyces cerevisiae strain in a glucose and xylose medium (YPDX) with 3.5 g/L acetic acid is shortened by 24 h. The fermentation period of the Saccharomyces cerevisiae strain to produce ethanol through co-utilization of glucose and xylose is shortened by 20 h. The growth of the Saccharomyces cerevisiae strain in a glucose and xylose medium (YPDX) with a mixed inhibitor and the ethanol production of the Saccharomyces cerevisiae strain through the co-fermentation of glucose and xylose are superior to those of a control strain.

A method for controlled production of glyceric acid includes, during the glyceric acid fermentation process, real-time online monitoring of at least one of the respiratory quotient and redox potential in the fermentation liquid as well as the fermentation process specific growth rate, and controlling their values within the following ranges: 0.1˜1.5 for respiratory quotient, −300˜50 mV for redox potential, 0.05˜0.8 for specific growth rate. Process parameters for this method are controlled within predetermined ranges by online monitoring at least one of respiratory quotient (RQ) and redox potential as well as the specific growth rate in the fermentation process, thereby meeting the growth requirements of bacteria, effectively promoting the glycerol metabolism and synthesis and improving the conversion rate.