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NH+/4‐N assimilation by Rhodobacter capsulatus ATCC 23782 grown axenically and non‐axenically in N and C rich media
Author(s) -
Suhaimi M.,
Liessens J.,
Verstraete W.
Publication year - 1987
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1987.tb02380.x
Subject(s) - rhodobacter , axenic , light intensity , photobacterium , biology , chemistry , food science , bacteria , biochemistry , gene , physics , mutant , vibrio , optics , genetics
Assimilation of NH+/4‐N and formation of cell biomass in Rhodobacter capsulatus ATCC 23782 were studied in batch cultures as a function of N and C concentration and light intensity. Growth occurred satisfactorily up to N and C levels of 1.2 and 6.0g/1, respectively. The maximum biomass density achieved was 2.3 g biomass‐C/l at 0.8 g N/l and 4.0g C/l. Media containing initial C/N ratios of 5 provided good growth and almost complete assimilation and recovery of NH+/4‐N and lactate‐C, respectively. A light intensity of about 120 μE/m 2 /s was adequate for efficient growth. At low levels of NH+/4‐N (<0.05 g N/l), the photobacterium could not maintain dominance under non‐axenic growth conditions. Chloroxuron was necessary to prevent algal overgrowth. At concentrations of 0.2 and 0.4 g NH+/4‐N/l, the photo‐bacterium maintained dominance over several months under the appropriate conditions of temperature (30°C), light intensity (120μE/m 2 /s), carbon supply (C/N = 5) and cell residence time (5.5d). The protein of Rhb. capsulatus ATCC 23782 was rich in essential amino acids.