Optimising biocatalyst design for obtaining high transesterification activity by α-chymotrypsin in non-aqueous media

Table 2 The effects of trehalose concentration on the activity (initial rates) of the α-chymotrypsin precipitated by n-propanol in octane. The experiments were carried out in triplicate. The percentage error in a set was within 7 percent.

Starting trehalose (percent wv^-1)	percent trehalose precipitated	Enzyme loading^a (weight percentage)	Initial rate^b (nmoles mg^-1min^-1)	Visual morphology of enzyme precipitate	Precipitation of trehalose in propanol (control)
0	0	-	16.6	Powder (EPRP)	No precipitation
2	65	38.9	40.0	Powder (EPRP)	No precipitation
5	90	15.5	45.2	Powder (EPRP)	No precipitation
10	94	7.5	63.2	Powder-crystalline	No precipitation
15	88	5.9	120.0	Crystalline	Precipitation
20	85	4.6	125.1	Crystalline	Precipitation
25	78	4.0	143.2	Crystalline	Precipitation
30	76	3.5	150.5	Crystalline	Precipitation
35	72	3.1	152.0	Crystalline	Precipitation
40	70	2.8	151.2	Crystalline	Precipitation
45	65	2.3	96.4	Crystalline	Precipitation
Saturated trehalose solution	60	1.5	87.4	Crystalline	Precipitation
PCMC (K₂SO₄)	-	5.8	132.5	Crystalline	Precipitation

^a $percent enzyme (w/w) = \frac{mg protein precipitated}{(mg of protein precipitated + mg of core material precipitated)} \times 100$
The amount of protein precipitated in each case was 0.83 mg.
^bInitial rates were calculated from the aliquots taken over 10 to 60 min. The percentage conversions during these time periods were 1–30 percent and in a linear range.

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