title: Biomass recycling from a riboflavin cultivation with B. subtilis: lysis, extract production and testing as substrate in riboflavin cultivation.
abstract: Autolysis of riboflavin-producing B. subtilis can be induced by pH, lack of carbon source, and the buffer system. Stress factors like temperature shift or oxygen dearth enhance the autolysis process. After cultivation of a riboflavin-producing strain, the pH of the whole culture broth was adjusted to 6.5-7.5. At a temperature of 40 degrees C, autolysis started after 1 h. Adding a defined amount of commercially available endo- and exo-proteases enhanced both auto- and proteo-lysis. Optimization of endo- and exo-protease concentrations and of the time increased the degree of proteolysis. Additionally, the amount of DNA and Protein trapped in the riboflavin crystals could be significantly reduced by autolysis. After autolysis, the cultivation broth was centrifuged and the supernatant was cross-flow filtrated with a cut off of 10 kDa. Using this autolysate instead of yeast extract as a medium component for riboflavin production with B. subtilis, a riboflavin yield of 77% was obtained in comparison with the standard cultivation on yeast extract.
authors.affiliation: DSMNutritional Products GmbH, Emil-Barellstr. 3, D-79639 Grenzach-Wyhlen, Germany.
authors.forename: Karlheinz
authors.initials: K
authors.lastname: Bretz
authors.forename: Stefan
authors.initials: S
authors.lastname: Ilijevic
authors.forename: Marlene
authors.initials: M
authors.lastname: Grüneberg
authors.forename: Ulrike
authors.initials: U
authors.lastname: Becker
authors.forename: Christoph
authors.initials: C
authors.lastname: Syldatk
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D018533:Biomass; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D003470:Culture Media / Q000378:metabolism / Q000494:pharmacology; D005285:Fermentation; D005486:Flavin Mononucleotide / Q000737:chemistry; D016680:Genome, Bacterial; D006863:Hydrogen-Ion Concentration; D010447:Peptide Hydrolases / Q000737:chemistry; D012256:Riboflavin / Q000096:biosynthesis* / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D003470:Culture Media; D012972:Sodium Hydroxide; D002244:Carbon; D005486:Flavin Mononucleotide; D010447:Peptide Hydrolases; D012256:Riboflavin