Bioprocess

Bioprocess Integration – LM3452
Assignment 1

September 23, 2013

Enzymatic conversion of lysine to 1,5-diaminopentane

Sebastiaan Keuter
Wouter Overbeek

1545558
4058356

Question 1
Table 1: Acid dissociation constants Ka,i of lysine, CO2 and 1,5-diaminopentane. Where index “i” is depicts the group arranged from

Compound lysine CO2
1,5-diaminopentane

Ka,1
10-2.2
10-6.4
10-9.1

Ka,2
10-9.0
10-10.3
10-10.3

Ka,3
10-10.5
-

Question 2
Figure 1 shows the reaction equation for the decarboxylation of lysine in both structures and molecular formulas. The charge for every compound is also indicated based on the pKa of the respective compounds.

Lysine

enzyme

Diaminopentane

H2O

+ CO2 + Cl-

HCl
HCO3-+H+
C6H16O2N2+

C5H16N22+ + CO2 + ClHCl

Figure 1: Reaction equation for the enzymatic conversion of lysine to diaminopentane and CO 2.

Bioprocess Integration – LM3452
Assignment 1

September 23, 2013

Question 3
To achieve a high extent of bio-catalytic conversion it is important to have a low product concentration. When comparing a PFR, CSTR and CSTRs, a CSTR is undesired since the product concentration is high everywhere in a CSTR. Both a CSTRs and PFR have a low product concentration at the beginning of the reaction flow. In a PFR the reaction is more efficient, the concentration of substrate drops more rapidly than in CSTRs. However, when addition of acid/base or removal of gases is necessary the CSTRs is more desired. Since it is assumed that the pH remains constant in this process, the PFR is preferred.
Question 4
Table 2: Kinetic data of immobilized lysine carboxylase.

Vmax,0 (mol/(L h))
0.5
1
2
4

T (°C)
20
30
40
50

KM (mol/L)
0.001
0.001
0.001
0.001

t½ (days)
540
270
135
67.5

For a Plug Flow Reactor (PFR) the mass that enters the reactor will also come out. We consider a reaction A  B. Therefore accumulation of lysine (A) equals production plus the flow in