title: Extracellular production of L-ascorbic acid by Chlorella protothecoides, Prototheca species, and mutants of P. moriformis during aerobic culturing at low pH.
abstract: Nine strains of Chlorella protothecoides and 43 strains representing the five species of Prototheca were screened in flask culture for their ability to synthesize L-ascorbic acid (AA). Ascorbic acid was detected in all strains, ranging from 4.8 to 0.38 mg AA g x (-1) of dry cells. Organisms selected for further study grew well and maintained their AA productivity above a pH of 3.5. They can produce AA using a variety of carbon and nitrogen sources. Aerobic fermentation of selected strains resulted in extracellular accumulation of AA up to 76 mg x l(-1). By classical mutagenesis and selection methods, we created mutants of Prototheca moriformis ATCC 75669 that produced greater quantities of AA than the wild-type strain (78.4 vs 21.9 mg AA g x (-1) of cells). A process based on extracellular production could greatly reduce the cost of AA manufacture by eliminating the need for extraction of the AA from the cells.
authors.affiliation: Bio-Technical Resources, 1035 South 7th Street, Manitowoc, WI 54220, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Running
authors.forename: D K
authors.initials: DK
authors.lastname: Severson
authors.forename: K J
authors.initials: KJ
authors.lastname: Schneider
mesh_terms: D000332:Aerobiosis; D001205:Ascorbic Acid / Q000096:biosynthesis / Q000378:metabolism*; D002708:Chlorella / Q000378:metabolism*; D003470:Culture Media; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D011525:Prototheca / Q000235:genetics / Q000378:metabolism*; D012641:Selection, Genetic; D013696:Temperature; D013997:Time Factors
chemical_list: D003470:Culture Media; D008274:Magnesium; D001205:Ascorbic Acid