Njc. Fong et al., Carotenoid accumulation in the psychrotrophic bacterium Arthrobacter agilis in response to thermal and salt stress, APPL MICR B, 56(5-6), 2001, pp. 750-756
A psychrotrophic strain of Arthrobacter agilis, isolated from Antarctic sea
ice, grows from 5 degreesC to 40 degreesC and in culture media containing
0-10% (w/v) NaCl. Maximum growth rate occurred at 30-35 degreesC with a dra
stic decline as the cultivation temperatures diverged. Adaptation to extrem
es of low temperature may be partially attributed to the production of the
C-50 carotenoid bacterioruberin, and its glycosylated derivatives. Lowering
of the cultivation temperature resulted in a concomitant increase in carot
enoid production, which may contribute to membrane stabilisation at low tem
perature. Maximum biomass accumulation occurred at 5-30 degreesC with a ten
fold reduction at 40 degreesC. Changes in growth rates were minimal in cult
ure media containing 0-2% (,w/v) NaCl at 10 degreesC while a gradual decrea
se in growth rates occurred at higher salinity. Biomass accumulation at dif
ferent salinity followed a trend similar to that observed with different cu
ltivation temperatures. Maximum biomass accumulation was observed in cultur
e media containing 0-5% (w/v) NaCl with a tenfold reduction at 10% (w/v) Na
Cl. Carotenoid production also decreased as salinity increased.