Part:BBa_K2617000

Xyn10D-Fae1A：Bifunctional xylanase/ferulic acid esterase

Xyn10D-fae1A is a bifunctional enzyme, which has the activity of ferulic esterase and xylanase. Feruloyl esterase can hydrolyze ferulic acid ester groups, which are responsible for attaching in complex cellular cell wall structures. Xylanase can hydrolyze plant cell wall component xylan. It can cut the β-1,4 glycosidic bond between the xylose residues in the xylan backbone. This part is responsible for pretreatment of straw.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 534
  Illegal AgeI site found at 381
  Illegal AgeI site found at 628
  
• 1000
  INCOMPATIBLE WITH RFC[1000]

  Illegal SapI.rc site found at 1236
  

Characterization

Molecular weight

This halohydrin dehalogenase gene codes for a protein of 726 amino acids with a molecular mass of 82.3 kDa.

Detection of ferulic acid

To detect the expression of piGEM2018-Module001, we will convert the piGEM2018-Module001 strain BL21(DE3) to co-culture with straw culture medium. The supernatant was collected 12 hours later and then detected ferulic acid by gas chromatography. Gas chromatographic procedure for 80 ℃ to 130 ℃, rising per minute 10 ℃; 130 ℃ to 190 ℃, rising per minute 2 ℃; 190 ℃ to 230 ℃, rising per minute 10 ℃. The melting point of ferulic acid is 169-173 ℃ and the boiling point is 372.3 ℃ at one atmospheric pressure. In the case of ferulic acid in gas chromatography with nitrogen as carrier gas, ferulic acid will undergo the following reaction and decompose into 9 carbon compounds.

Fig. 1 Ferulic acid decomposition equation.

The peak time of ferulic acid decomposition products was about 22-23min. The internal standard is carvacrol, and its peak time is after ferulic acid decomposition products. We compared them through four groups of experiments: only medium group, straw plus medium group, BL21(DE3) original strain group, and transformed piGEM2018-Module001 group. The following four graphs were obtained, and ferulic acid was generated by comparison.

Fig. 1 Quantitative detection of ferulic acid.

Enzyme activity of xylanase

Fig. 2 Standard Curve of Xylose.

Fig. 3 Xylanase Activity on Xylan. Data were measured inphosphate buffer solution at pH 6.0 and 40℃.

Enzyme activity of xylanase

Ferulic acid esterase can decompose ferulic acid p-nitrophenol ester to produce p-nitrophenol and ferulic acid. The strain BL21 (DE3) transformed with piGEM2018-Module001 was cultivated overnight and centrifuged to obtain the supernatant. The remaining bacteria were broken and broken products were obtained. DSMO solution of ferulic acid p-nitrophenol ester was added to phosphate buffer solution of 630 L pH=6.4 with a concentration of 400 L of 10 mmol/L. Heat preservation 5min at 40℃ and add 0.2ml sample solution. The initial OD values were measured before incubation. Gently mix and incubate 4h at 40 C, determine the final OD value and compare the difference.

Fig. 4 Enzyme Activity of Ferulic acid esterase. Data were measured in phosphate buffer solution at pH 6.4 and 40℃.