The hemicellulose-degrading enzyme system of the thermophilic bacterium Clostridium stercorarium: comparative characterisation and addition of new hemicellulolytic glycoside hydrolases

Table 4 Optimal reaction conditions of 13 hemicellulolytic glycoside hydrolases

Enzyme	pH_opt	pH range	T_opt (°C)	T range (°C)	Substrate
Bga2B	6.0	5.0–6.5	56.8	40–70	Xyloglucan
Bxl3B	5.5	5.0–6.5	65.6	48–72	Glucuronoxylan
Cel9Z	5.5	4.0–6.5	80.6	66–87	β-Glucan (barley)
Xyn10C	6.0	4.5–7.5	70.6	56–77	Arabinoxylan
Xyn10B	5.5	4.0–7.0	75.6	61–79	Arabinoxylan
Xyn10D	6.0	5.0–7.0	65.6	58–66	Arabinoxylan
Xyn11A	5.5	4.5–7.0	66.8	56–74	Arabinoxylan
Man26A	5.5	5.0–6.0	61.8	48–66	Galactomannan
Bga35A	5.5	5.0–6.0	60.6	40–67	Galactan (lupin)
Axh43A	6.0	5.5–6.5	60.6	49–64	Arabinoxylan
Arf43C	6.0	5.5–7.0	49.4	43–64	Pectic galactan (potato)
Abn43A	6.5	6.0–7.0	65.6	51–72	Arabinan
Arf51B	5.0	4.5–5.5	61.8	45–75	Arabinan

The enzymes were incubated with 0.5% of the indicated substrate at pH 4.0 to pH 8.0 (at 60 °C) and between 40 °C and 90 °C (at the enzymes’ optimal pH) for 30 min, 60 min (Bga2B, Bga35A and Arf51B) or 120 min (Bxl3B). Enzyme activities were determined by DNSA-based assay in triplicates. Borders for pH and T ranges were set to 60% of the highest activity

ISSN: 2731-3654