BioMed Research International

Research Article

Constitutive High Level Expression of an Endoxylanase Gene from the Newly Isolated Bacillus subtilis AQ1 in Escherichia coli

Table 2

Comparison of the activity at 55°C pH 7 of the supernatant from the fermentation broth after 24 hours of cultivation at 37°C in the different medium content of 𝐵 . 𝑠 𝑢 𝑏 𝑡 𝑖 𝑙 𝑖 𝑠 AQ1, 𝐵 . 𝑠 𝑢 𝑏 𝑡 𝑖 𝑙 𝑖 𝑠 DB104, and recombinant 𝐸 . 𝑐 𝑜 𝑙 𝑖 𝑠 at the same OD OR cell number per ml. The given values in activity assays are the means of triplicates independent experiment (± the standard deviation).
No.MediumLBLB xylan (1%)
(1)Endoxylanase activity of supernatant from original B. subtilis strain AQ172.6 ± 1 U/mL141.9 ± 1 U/mL
(306.2 ± 4.2 U/mg) (529.7 ± 5.6 U/mg)
(2)Endoxylanase activity of supernatant from original B. subtilis strain DB10416.47 ± 0.1 U/mL35.7 ± 0.26 U/mL
(105.71 ± 0.9 U/mg)(286.0 ± 2.1 U/mg)
(3)Endoxylanase activity of supernatant from rec E. coli (PGEMxynAQ1+promoter)586.9 ± 13.9 U/mL823.6 ± 3.5 U/mL
(2173.6 ± 51.4 U/mg)(2745.3 ± 11 U/mg)
(4)Endoxylanase activity of supernatant from E. coli (PGEMxynDB104+promoter)126.2 ± 3.9 U/ mL184.9 ± 5.2 U/mL
(573.6 ± 17.7 U/mg)(660.3 ± 18.6 U/mg)
(5)Endoxylanase activity of supernatant from E. coli (PGEMxynAQ1-promoter)N.D.4.6 ± 0.4 U/mL
(20.0 ± 1.7 U/mg)
(6)Endoxylanase activity of supernatant from rec E. coli (PGEM T easy only)N.D.N.D.
*N.D.: no activity was detected at standard assay condition.