Ethanol production of semi-simultaneous saccharification and fermentation from mixture of cotton gin waste and recycled paper sludge

Ethanol production from the steam-exploded mixture of 75% cotton gin waste and 25% recycled paper sludge in various conditions was investigated by semi-simultaneous saccharification and fermentation (SSSF) consisting of a pre-hydrolysis and a simultaneous saccharification and fermentation (SSF). Four cases were studied: 24-h pre-hydrolysis + 48-h SSF (SSSF 24), 12-h pre-hydrolysis + 60-h SSF (SSSF 12), 72-h SSF, and 48-h hydrolysis + 24-h fermentation (SHF). The ethanol concentration, yield, and productivity of SSSF 24 were higher than those of the other operations. A model of SSF was used to simulate the data for four components in SSF. The analysis of the reaction rates of cellobiose, glucose, cell, and ethanol using the model and the parameters from the experiments showed that there was a transition point of the rate-controlling step at which the cell growth control in the initial 2 h was changed to the cellobiose reaction control in later period during ethanol production of SSF from the mixture

Efficiency of Soil and Fertilizer Phosphorus Use in Time: A Comparison Between Recovered Struvite, FePO4-Sludge, Digestate, Animal Manure, and Synthetic Fertilizer

The aim of this study was to evaluate the phosphorus use efficiency (PUE) based on the plant reaction and changes in soil P bioavailability status in time by land application of recovered bio-based fertilizers, including struvite, FePO4-sludge, digestate, and animal manure, compared to synthetic triple super phosphate (TSP). First, product characteristics and P fractionations were assessed. Then, a greenhouse experiment was set up to evaluate plant growth and P uptake, as well as changes in P availability on sandy soils with both high and low P status. P soil fractions were determined in extracts with water (Pw), ammonium lactate (PAl), and CaCl2 (P-PAE) and in soil solution sampled with Rhizon samplers (Prhizon). Struvite demonstrated potential as a slow release, mixed nutrient fertilizer, providing a high P availability in the beginning of the growing season, as well as a stock for delayed, slow release. The addition of FePO4-sludge was not interesting in terms of P release, but resulted in the highest PUE regarding biomass yields. The conversion of animal manure by anaerobic (co)digestion and subsequent soil application of digestate improved the PUE. Finally, the additional use of Rhizon samplers is proposed for better understanding and categorization of different inorganic and organic P fertilizers in environmental legislation