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Production and characterisation of alginate from Azotobacter vinelandii
Author(s) -
Clementi Francesca,
Crudele Maria Antonietta,
Parente Eugenio,
Mancini Marco,
Moresi Mauro
Publication year - 1999
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(19990315)79:4<602::aid-jsfa224>3.0.co;2-n
Subject(s) - industrial fermentation , azotobacter vinelandii , fermentation , chemistry , food science , growth rate , chemical composition , bacterial growth , kinetics , nitrogen , biochemistry , organic chemistry , bacteria , biology , nitrogenase , geometry , mathematics , nitrogen fixation , genetics , physics , quantum mechanics
The alginate produced from glucose by Azotobacter vinelandii DSM 576 in the shaken‐flask (SF) scale wascharacterised in terms of chemical composition and average molecularmass ( M n ). Its chemical composition waspractically independent of the fermentation time with an averagecontent in uronic acids of 0.66±0.09 g/g, a highproportion of mannuronic acid ( M =0.75±0.04) and a mean acetylation degree of18.5±7.9%. On the contrary, M n reached a maximum value of ca. 220 kDa after 40–42 hfermentation and then decreased to 60 kDa in the following20–22 hours. The fermentation process was scaled‐up in alaboratory fermenter (LF) and the kinetics of alginateproduction was classified of the mixed ‐ growth ‐ associated product formation type with acontribution of non‐growth associated production of the orderof 70 or 80% depending on the LF or SF scale used. However,the rate of M n increase was found to be strictlygrowth‐associated, since alginate depolymerisation wasobserved as soon as the exponential cell growth rate stopped and thiscoincided with ammoniac nitrogen levels smaller than 10–15 g m −3 . © 1999 Society of Chemical Industry