. 2009 Nov 30;76(3):971–973. doi: 10.1128/AEM.02463-09

TABLE 1.

Effect of manipulating the target genes identified by transcriptome profiling on the specific activities of lipase displayed on the E. coli cell surface

Target gene	Change in gene expression levels (log₂)^a	Lipase sp act (U/mg of lyophilized cells)^b		Relative lipase activity (%)^c
Target gene	Change in gene expression levels (log₂)^a	Knockout strain	Amplification strain	Knockout strain	Amplification strain
pspABCDE	2.4 to 5.8	1,110 ± 78	1,180 ± 78	57.2 ± 4.02	60.8 ± 4.02
gadBC	−2.6 to −2.1	815 ± 83	92,300 ± 407	42.0 ± 4.28	4,760 ± 21.0

The values indicate the changes in the expression levels of the target genes in a recombinant E. coli strain displaying lipase compared with those of a control strain containing the backbone plasmid, determined by DNA microarray analysis.

One unit of lipase activity was defined as the amount of enzyme releasing 1 micromole of p-nitrophenol per minute. All measurements were independently performed in triplicates. The values after the ± sign represent the standard deviation.

Relative lipase activity was calculated by assuming the lipase activity measured in control strain without target gene manipulation (1,940 ± 118) as 100%.