Vitamin B12 is synthesized in nature exclusively by microorganisms but is required as a growth factor by all animals.
In humans, a major deficiency of vitamin B12
leads to a debilitating condition called pernicious anemia, characterized by low production of red blood cells and nervous
system disorders.
For industrial production of vitamin B12, microbial strains are employed that have been specifically selected for their high yields of the vitamin. Species of the bacteria Propionibacterium and Pseudomonas are the main commercial producers, especially Propionibacterium freudenreichii. The
metal cobalt is present in vitamin B12, and commercial yields of the vitamin are greatly increased by addition of small amounts of cobalt to the culture medium.
Riboflavin (Figure 15.8b) is the parent compound of the flavins FAD and FMN, coenzymes that play important roles in enzymes for oxidation–reduction reactions. Riboflavin is synthesized by many microorganisms, including bacteria, yeasts,
and fungi. The fungus Ashbya gossypii naturally produces several grams per liter of riboflavin and is therefore the main organism
used in microbial production. However, despite this good yield, there is significant economic competition between the microbiological process and strictly chemical synthesis. Please see Appendix 5 for the structure of Viatmin B12 and Riboflavin.
Vitamin B12 is synthesized in nature exclusively by microorganisms but is required as a growth factor by all animals. In humans, a major deficiency of vitamin B12leads to a debilitating condition called pernicious anemia, characterized by low production of red blood cells and nervoussystem disorders. For industrial production of vitamin B12, microbial strains are employed that have been specifically selected for their high yields of the vitamin. Species of the bacteria Propionibacterium and Pseudomonas are the main commercial producers, especially Propionibacterium freudenreichii. Themetal cobalt is present in vitamin B12, and commercial yields of the vitamin are greatly increased by addition of small amounts of cobalt to the culture medium.Riboflavin (Figure 15.8b) is the parent compound of the flavins FAD and FMN, coenzymes that play important roles in enzymes for oxidation–reduction reactions. Riboflavin is synthesized by many microorganisms, including bacteria, yeasts,and fungi. The fungus Ashbya gossypii naturally produces several grams per liter of riboflavin and is therefore the main organismused in microbial production. However, despite this good yield, there is significant economic competition between the microbiological process and strictly chemical synthesis. Please see Appendix 5 for the structure of Viatmin B12 and Riboflavin.
การแปล กรุณารอสักครู่..