Provided is a Bacillus subtilis natto strain ST-1008, deposited under the accession number CGMCC No. 17894. Also provided is a method for producing MK-7. The method comprises: culturing the Bacillus subtilis natto strain of CGMCC No. 17894 in a culture medium so as to produce MK-7 in the strain cell and the culture medium, and recovering and purifying MK-7 from the strain cell and the culture medium. Also provided are a MK-7 preparation, a MK-7 pure premix, and a pure MK-7.

Controlled coenzyme Q.sub.10 (CoQ.sub.10) fermentation production processes and methods for controlling the CoQ.sub.10 fermentation production processes are provided in the present disclosure. The processes may include growing a microbial culture of bacteria by providing a carbon source and an oxygen source for a predetermined period of time, thereby producing CoQ.sub.10-containing bacteria, carbon dioxide, and lactate in the bacterial culture. During various stages of the production process, the concentration of carbon dioxide may be maintained at predetermined levels, respectively. Alternatively or additionally, during various stages of the production process, the concentration of lactate may be maintained at predetermined levels, respectively.

The use of a cytochrome P-450 enzyme comprising SEQ ID NO: 3, or a variant enzyme having at least 70% identity thereto and having CYP-450 activity, for the hydroxylation of an organic compound.

The use of a cytochrome P-450 enzyme comprising SEQ ID NO: 3, or a variant enzyme having at least 70% identity thereto and having CYP-450 activity, for the hydroxylation of an organic compound.

The present application relates to a method for extracting coenzyme Q10 and a phospholipid from a coenzyme Q10 fermentation bacterium powder. The method is characterized in that the fermentation bacterium powder of a coenzyme Q10 production strain is subjected to extraction with a mixed solvent of which the three-dimensional Hansen solubility parameter is between 21 and 23 (J/cm.sup.3).sup.1/2 and the hydrogen bonding solubility parameter thereof is between 10 and 12 (J/cm.sup.3).sup.1/2. The present invention can efficiently extract two products, namely coenzyme Q10 and a phospholipid, from the coenzyme Q10 fermentation bacterium powder; the process thereof is highly operable, easy to be industrialized, and can provide a product with high purity and yield, having great economic benefit.

The present application relates to a method for extracting coenzyme Q10 and a phospholipid from a coenzyme Q10 fermentation bacterium powder. The method is characterized in that the fermentation bacterium powder of a coenzyme Q10 production strain is subjected to extraction with a mixed solvent of which the three-dimensional Hansen solubility parameter is between 21 and 23 (J/cm.sup.3).sup.1/2 and the hydrogen bonding solubility parameter thereof is between 10 and 12 (J/cm.sup.3).sup.1/2. The present invention can efficiently extract two products, namely coenzyme Q10 and a phospholipid, from the coenzyme Q10 fermentation bacterium powder; the process thereof is highly operable, easy to be industrialized, and can provide a product with high purity and yield, having great economic benefit.

Provided are improved methods for Vitamin K, including but not necessarily limited to MK-7 production through bacterial fermentation using biofilm reactors. Fed-batch addition of carbon sources, such as glucose, are used as the base media in biofilm reactors. Fed-batch strategies are shown to be significantly effective in glucose-based medium, increasing the end-product concentrations to more than 2-fold higher than the level produced in suspended-cell bioreactors.

Provided are improved methods for Vitamin K, including but not necessarily limited to MK-7 production through bacterial fermentation using biofilm reactors. Fed-batch addition of carbon sources, such as glucose, are used as the base media in biofilm reactors. Fed-batch strategies are shown to be significantly effective in glucose-based medium, increasing the end-product concentrations to more than 2-fold higher than the level produced in suspended-cell bioreactors.

A recombinant microorganism, a preparation method thereof and its application in the production of coenzyme Q10. Specifically, the present disclosure provides a method of exogenously introducing a gene encoding the global regulatory protein irrE to construct a recombinant microorganism. This recombinant microorganism is suitable for producing coenzyme Q10 by fermentation method, and is particularly suitable for producing oxidized coenzyme Q10. The recombinant microorganism of the present disclosure has stress resistance, and has good tolerance against harsh environments including high osmotic pressure and high redox potential, thus making it possible to significantly increase the yield of coenzyme Q10, especially the yield of oxidized coenzyme Q10.

A recombinant microorganism, a preparation method thereof and its application in the production of coenzyme Q10. Specifically, the present disclosure provides a method of exogenously introducing a gene encoding the global regulatory protein irrE to construct a recombinant microorganism. This recombinant microorganism is suitable for producing coenzyme Q10 by fermentation method, and is particularly suitable for producing oxidized coenzyme Q10. The recombinant microorganism of the present disclosure has stress resistance, and has good tolerance against harsh environments including high osmotic pressure and high redox potential, thus making it possible to significantly increase the yield of coenzyme Q10, especially the yield of oxidized coenzyme Q10.