Isolation and characterization of psychrophiles producing cold-active beta-galactosidase.
OBJECTIVE
The present study was conducted to screen for psychrophilic micro-organisms that are able to hydrolyse lactose at low temperature, and to examine the cold-active beta-galactosidase produced by the isolated psychrophilic micro-organisms.


RESULTS
Psychrophilic bacteria, which grow on lactose as a sole carbon source, were isolated from soil from Hokkaido, Japan. The phenotype and sequence of 16S rDNA of the isolated strains indicated a taxonomic affiliation to Arthrobacter psychrolactophilus. The isolated A. psychrolactophilus strains were able to grow on lactose at below 5 degrees C, and showed cold-active beta-galactosidase activity, which was highly specific at even 0 degrees C.


CONCLUSIONS
Facts in this study may indicate the possibility that the isolated strains produce novel beta-galactosidases that are able to hydrolyse lactose at low temperature, although some strains have isozymes.


CONCLUSIONS
It may be possible that the cold active beta-galactosidases from the isolated strains can be applied to the food industry, e.g. processing of milk and whey below 5 degrees C.
Nakagawa
T
T
Department of Food Science and Technology, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan.
Fujimoto
Y
Y
Uchino
M
M
Miyaji
T
T
Takano
K
K
Tomizuka
N
N
D001173:Arthrobacter / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005524:Food Technology; D007564:Japan; D008855:Microscopy, Electron, Scanning; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D001616:beta-Galactosidase / Q000096:biosynthesis*
D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D001616:beta-Galactosidase