ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary Two fermentation processes for the tryptophan-regulated expression of active HIV protease (HIV-1 prt) in Escherichia coli are described. Since overexpression of HIV-1 prt results in cell death, stringent control of product expression was necessary to attain high enzyme levels. Such control was achieved by separation of growth and production phases in a two-step process or by implementation of nutrient feed in a one-step process. When the two-stage process was used, soluble product was detectable only when induction occurred at low culture density (A 550 〈 3.5). Short induction periods of 1–2 h and rapid harvesting were necessary to recover active product. Similar results were obtained when the single-stage process was operated at 37°C; however, cultivation and induction at 28°C resulted in active enzyme formation following induction at increased cell density (A 550=10).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00164410
