TABLE 3 .
Soluble sugar production following digestion of hatched wheat straw and pretreated wheat straw over a 24-h incubation period by various enzyme combinationsa
| Substrate | Enzyme combination |
mg/g substrate ± SD (μM/g substrate) |
||||||
|---|---|---|---|---|---|---|---|---|
| Arabinose | Xylose | Xylobiose | Xylotriose | Glucose | Cellobiose | Cellotriose | ||
| Untreated wheat straw |
WT free enzymes (six enzymes) |
ND | 17 ± 1 (110) | 28 ± 0.8 (98) | ND | 3 ± 1 (17) | 41 ± 3 (119) | ND |
| Hexavalent designer cellulosomes |
5 ± 3 (30) | 22 ± 2 (145) | 35 ± 4 (125) | ND | 5 ± 0.6 (30) | 44 ± 5 (129) | ND | |
| Native cellulosomes |
8 ± 2 (55) | 1 ± 0.5 (10) | 80 ± 8 (282) | 8 ± 2 (19) | 4 ± 0.6 (22) | 105 ± 11 (306) | 9 ± 3 (18) | |
| WT free enzymes + Bgl1C |
ND | 15 ± 4 (101) | 37 ± 8 (132) | ND | 36 ± 7 (198) | ND | ND | |
| Hexavalent designer cellulosomes + Bgl1C |
3 ± 1 (23) | 33 ± 4 (217) | 47 ± 5 (167) | ND | 37 ± 3 (208) | ND | ND | |
| Native cellulosomes + Bgl1C |
7 ± 3 (48) | 11 ± 1 (70) | 106 ± 12 (375) | ND | 58 ± 7 (322) | 34 ± 3 (100) | ND | |
| Chemically pretreated wheat straw |
WT free enzymes (six enzymes) + Bgl1C |
11 ± 4 (70) | 70 ± 5 (466) | 300 ± 13 (1,062) | 9 ± 2 (22) | 13 ± 2 (71) | 19 ± 3 (56) | ND |
| Hexavalent designer cellulosomes + Bgl1C |
17 ± 6 (112) | 32 ± 4 (211) | 113 ± 9 (400) | ND | 9 ± 1 (49) | 11 ± 1 (31) | ND | |
| Native cellulosomes + Bgl1C + Xyl43A |
13 ± 2 (89) | 29 ± 2 (194) | 212 ± 11 (750) | 12 ± 1 (28) | 11 ± 1 (60) | 375 ± 15 (1,094) | ND | |
| Biologically pretreated wheat straw |
WT free enzymes (six enzymes) + Bgl1C |
0.3 ± 3 (2) | 34 ± 2 (225) | 256 ± 14 (906) | ND | 2 ± 0.7 (11) | 21 ± 2 (60) | ND |
| Hexavalent designer cellulosomes + Bgl1C |
9 ± 2 (57) | 29 ± 2 (192) | 107 ± 6 (378) | ND | 1 ± 0.4 (6) | 34 ± 4 (98) | ND | |
| Native cellulosomes + Bgl1C + Xyl43A |
11 ± 3 (74) | 40 ± 6 (268) | 201 ± 10 (712) | ND | 5 ± 2 (29) | 89 ± 8 (260) | ND | |
a
Data were obtained by high-performance liquid chromatography analysis. Values for xylose and glucose were corroborated using a sugar assay kit. An unidentified peak, present only after enzymatic treatments, eluted at ~4 min (between the xylose and xylobiose peaks), is possibly a modified monosaccharide, as previously described (13, 14, 20). ND, not detected.