Fermentation of acid hydrolysates from olive-tree pruning debris by Pachysolen tannophilus

Abstract

The influence of the type and concentration of acid in the hydrolysis process and its effect on the subsequent fermentation by Pachysolen tannophilus (ATCC 32691) to produce ethanol and xylitol was studied. The hydrolysis experiments were performed using hydrochloric, sulphuric and trifluoroacetic acids in concentrations ranging from 0.1 to 1.0 N, a temperature of 90 degrees C, and a time of 240 min. The fermentation experiments were conducted on a laboratory scale in a batch-culture reactor at pH 4.5 and 30 degrees C. The hydrolysis with the highest acid concentration produced the complete solubilization of hemicellulose to monosaccharides. The highest values for the specific rate of ethanol production were registered in cultures hydrolyzed with trifluoroacetic acid, and values were found to decrease as the acid concentration increased. The highest values of overall ethanol yields (Y(E/s)G = 0.37 kg kg(-1)) were also found in the fermentation of the hydrolysates of trifluoroacetic acid.

Detoxification of rice straw and olive tree pruning hemicellulosic hydrolysates employing Saccharomyces cerevisiae and its effect on the ethanol production by Pichia stipitis

“…4 Debris from olive tree pruning represents a great volume of biomass in Spain, especially in Andalucia, where annual production reaches 3.9 million tons, varying between 1700 and 3000 kg/(ha year), depending on culture conditions. 2,5 Due to the large volumes of this residue and the environmental damage associated with this biomass, the possibility of valuing these byproducts from the agricultural industry has been suggested. 1,2 The major organic constituents of lignocellulosic materials are cellulose (30−50%), hemicellulose (20−40%) and lignin (15−30%).…”

“…2,5 Due to the large volumes of this residue and the environmental damage associated with this biomass, the possibility of valuing these byproducts from the agricultural industry has been suggested. 1,2 The major organic constituents of lignocellulosic materials are cellulose (30−50%), hemicellulose (20−40%) and lignin (15−30%). 6 The hemicellulosic fraction of the residues can be recovered by dilute acid hydrolysis, generating mainly D-xylose monomers in the rice straw hemicellulosic hydrolysate 1 and a combination of D-xylose and D-glucose monomers in olive tree pruning hydrolysate as well.…”

Production of bioalcohols and antioxidant compounds by acid hydrolysis of lignocellulosic wastes and fermentation of hydrolysates with Hansenula polymorpha

“…Moya et al. achieved an overall ethanol yield of 0.33 g/g using P. tannophilus in the fermentation of hydrolysates of olive‐tree pruning debris from hydrolysis with sulphuric acid. The low values of yields obtained in this work can be due to the strong inhibition caused by the acetic acid and the high concentration of phenolic compounds that were found in the sunflower‐stalk hydrolysates.…”

Comparison of saccharification process by acid and microwave-assisted acid pretreated swine manure

“…Ethanolization based on lignocellulosic-containing materials may minimize the strain on using the current cornstarch-based resource reserves [8], since corn production for ethanol will compete with food and feed production for the limited agricultural land [7]. Researches on bio-ethanol production from lignocellulosic waste materials, such as crop residues [9], forest products industry wastes [10,11], bagasse [12], municipal solid waste [13], paper sludge [14], as well as dairy and cattle manures [7] have been conducted. However, little information concerning ethanol production from swine manures is available, especially in China.…”