Lyoprotection and stabilization of laccase extract from Coriolus hirsutus, using selected additives

AMB Express

Table 1 Effect of different lyoprotectants on laccase stability, nature of the extract and its solubility

Extract	Residual laccase activity (%)^a	Nature of extract^b	Solubility^c
Fresh without additive	100.0	Liquid	n.d.
Lyophilized without additive	92.1 (6.2)^e	Sticky	+
Lyophilized with 0.5% (w/v) BSA	17.3 (11.6)	Powder	+++
Lyophilized with 5% (w/v) mannitol	98.2 (2.3)	Powder	+++
Lyophilized with 1% (w/v) dextran 6 kDa	241.0 (5.4)	Powder	+++
Lyophilized with 5% (w/v) sucrose	141.2 (14.0)	Collapsed	−
Lyophilized with 5% (w/v) mixture (BSKS)^d	184.3 (2.5)	Collapsed	++
Lyophilized with 70% (w/w) KCl	n.d.	Powder	+++

n.d. Not detected
^aResidual laccase activity (%) was defined as the specific activity (nmol product/mg protein/min) of the lyophilized trial in comparison to that of the fresh ultrafiltrated enzymatic extract before lyophilization without additive
^bNature of the extract was defined as the final texture of the lyophilized enzymatic
^cDegree of solubility of the enzyme preparation in sodium acetate buffer (0.1 M, pH 5.0), after lyophilization, was expressed with qualitative evaluation +++, ++, + and − from the highest solubility to the lowest one, respectively, taking into consideration the required time for solubilization
^dMixture was composed of sodium benzoate/potassium sorbate/sorbitol (BKSS) (1.5:1.0:98.5, w/w/w)
^eRelative percentage standard deviation was defined as the standard deviation of laccase triplicate trial divided by their respective means, multiplied by 100