High productivity of ectoines by Halomonas boliviensis using a combined two-step fed-batch culture and milking process.

• A process comprising two-step fed-batch cultivation has been investigated for the production of ectoines using the halophilic bacterium Halomonas boliviensis DSM 15516(T). The first cultivation was performed under optimal conditions for cell growth and resulted in cell mass concentration of about 41gl(-1) after 24h of cultivation. During the second cultivation at higher salt concentration, accumulation of ectoines increased while cell mass decreased with increasing salt concentration. Maximum productivity of total ectoines reached was 10gl(-1)d(-1) with ectoine concentration of 6gl(-1) and hydroxyectoine concentration of 8gl(-1) after 9h of cultivation at 18.5% NaCl, which is among the highest reported so far. H. boliviensis cells were further recycled for the production process after releasing the ectoines. About 75% of the accumulated ectoines were released by subjecting the cells to hypoosmotic shock. On subsequent reincubation in a medium containing higher salt concentration the cells were able to re-synthesize the ectoines resulting in a global productivity of 11.1gl(-1)d(-1), and ectoine and hydroxyectoine productivities of 9.1gl(-1)d(-1) and 2.0gl(-1)d(-1), respectively.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Industriell bioteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Industrial Biotechnology (hsv//eng)

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