Fresh white GP waste was collected from a local winery in Queretaro. For the experimental work, seeds and stems were removed, the remaining waste was pressed, and the solid part was referred to as GP waste. The characterization of GP waste is shown in Table 1. Fresh bovine rumen with a total solid content of 0.172 ± 0.01 g/g was used as a source of microorganisms, and it was collected from a municipal slaughterhouse at Queretaro, Mexico. The suitability of ruminal fluid as inoculum was determined in a previous study (Villegas-Rodríguez & Buitrón 2021); therefore, that inoculum was considered to use in this investigation.
Contents of soluble compounds, hemicellulose, cellulose, lignin, and ash in white GP
| Parameters . | Value . |
|---|---|
| Soluble compounds (%) | 50.1 |
| Hemicellulose (%) | 4.5 |
| Cellulose (%) | 12.7 |
| Lignin (%) | 32.8 |
| Ash (%) | 0.002 |
| Total solids (g/g) | 0.18 ± 0.00 |
| Volatile solids (g/g) | 0.14 ± 0.00 |
| Soluble reducing carbohydrates (mg/g fresh grape pomace) | 24.0 ± 1.5 |
| Phenol compounds (mg gallic acid equivalents/g volatile solids of grape pomace) | 4.6 ± 0.3 |
| Parameters . | Value . |
|---|---|
| Soluble compounds (%) | 50.1 |
| Hemicellulose (%) | 4.5 |
| Cellulose (%) | 12.7 |
| Lignin (%) | 32.8 |
| Ash (%) | 0.002 |
| Total solids (g/g) | 0.18 ± 0.00 |
| Volatile solids (g/g) | 0.14 ± 0.00 |
| Soluble reducing carbohydrates (mg/g fresh grape pomace) | 24.0 ± 1.5 |
| Phenol compounds (mg gallic acid equivalents/g volatile solids of grape pomace) | 4.6 ± 0.3 |