Effect of Several Pretreatments on the Lactic Acid Production from Exhausted Sugar Beet Pulp (original) (raw)
Related papers
Feasibility of exhausted sugar beet pulp as raw material for lactic acid production
Journal of the Science of Food and Agriculture, 2020
BACKGROUNDExhausted sugar beet pulp pellets (ESBPP), a sugar industry by‐product generated after sugar extraction in the sugar production process, have been used as a raw material for lactic acid (LA) production via hydrolysis and fermentation by Lactobacillus casei. To design a more cost‐effective process, simultaneous saccharification and fermentation (SSF) of ESBPP is proposed in the present study. The effects of pH control, nutrient supplementation and solid addition in fed‐batch SSF on lactic acid production were investigated.RESULTSThe highest LA concentration (26.88 g L–1) was reached in fed‐batch SSF at a solid/liquid loading of 0.2 g mL–1, with pH control (by adding 30 g L–1 CaCO3 to the medium) and nutrient supplementation (by adding 20 mL of MRS medium per 100 mL of buffer). Under these conditions, a maximum productivity of 0.63 g L−1 h−1 was achieved, which is 2.7 times higher than that attained in the control experiment (SSF inoculated at time 0 h). However, a slightly ...
Food technology and biotechnology, 2018
This study compares the efficiency of lactic acid production by separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF) of sugar beet pulp, a byproduct of industrial sugar production. In experiments, sugar beet pulp was hydrolyzed using five commercial enzymes. A series of shake flask fermentations were conducted using five selected strains of lactic acid bacteria (LAB). The differences in the activities of the enzymes for degrading the principal sugar beet pulp components were reflected in the different yields of total reducing sugars. The highest yields after hydrolysis and the lowest quantities of insoluble residues were obtained using a mixture (1:1) of Viscozyme® and Ultraflo® Max. In the SHF process, only a portion of the soluble sugars released by the enzymes from the sugar beet pulp was assimilated by the LAB strains. In SSF, low enzyme loads led to reduction in the efficiency of sugar accumulation. The risk of carbon catabolic repr...
Acid hydrolysis of sugar beet pulp as pretreatment for fermentation
Bioresource Technology, 1994
Substrate pretreatment is a cost-sensitive operation in the production of ethanol from lignocellulosic materials. The general purpose of this work is to optimize substrate pretreatment by selectively solubilizing the hemicellulose fraction to render a cellulose-enriched fraction for further fermentation or enzyme hydrolysis. Hemicellulose hydrolyzate, usually a waste stream, is proposed to be fermented by the pentose-utilizing yeast Pichia stipitis. Sugar beet pulp (SBP) was chosen as a substrate due to its low lignin content which makes substrate pretreatment simpler and less expensive. Hemicellulose utilization is very important in the case of SBP, whose hemicellulose content is as high as 50%.
Effects of Enzyme and Solids Loading on Sugar Beet Pulp Hydrolysis
The commercial enzymes Viscozyme and Pectinex were tested separately and in combinations to determine their effect on pectin, hemicellulose, and cellulose hydrolysis of sugar beet pulp (SBP). Use of each product separately resulted in high levels of SBP hydrolysis, and no synergistic effects were found when they were used in combination. Viscozyme treatments showed higher levels of hemicellulose, pectin, and cellulose hydrolysis. Hydrolysis yields from hemicellulose and pectin in Pectinex treatments were 7% to 9% lower than in Viscozyme treatments; levels of cellulose hydrolysis were similar except that Pectinex treatments had a significantly higher percentage of cellobiose and correspondingly lower glucose. Increasing the solids loading from 10% to 16% in a batch process increased hydrolyzate sugar concentrations but decreased yields (g sugar g-1 SBP). Adding SBP in a fed-batch process did not improve SBP hydrolysis yields over the batch process.
Conversion of Exhausted Sugar Beet Pulp into Fermentable Sugars from a Biorefinery Approach
Foods, 2020
In this study, the production of a hydrolysate rich in fermentable sugars, which could be used as a generic microbial culture medium, was carried out by using exhausted sugar beet pulp pellets (ESBPPs) as raw material. For this purpose, the hydrolysis was performed through the direct addition of the fermented ESBPPs obtained by fungal solid-state fermentation (SSF) as an enzyme source. By directly using this fermented solid, the stages for enzyme extraction and purification were avoided. The effects of temperature, fermented to fresh solid ratio, supplementation of fermented ESBPP with commercial cellulase, and the use of high-solid fed-batch enzymatic hydrolysis were studied to obtain the maximum reducing sugar (RS) concentration and productivity. The highest RS concentration and productivity, 127.3 g·L−1 and 24.3 g·L−1·h−1 respectively, were obtained at 50 °C and with an initial supplementation of 2.17 U of Celluclast® per gram of dried solid in fed-batch mode. This process was ca...
Molecules
Lactic acid is a high-value molecule with a vast number of applications. Its production in the biorefineries model is a possibility for this sector to aggregate value to its production chain. Thus, this investigation presents a biorefinery model based on the traditional sugar beet industry proposing an approach to produce lactic acid from a waste stream. Sugar beet is used to produce sugar and ethanol, and the remaining pulp is sent to animal feed. Using Bacillus coagulans in a continuous fermentation, 2781.01 g of lactic acid was produced from 3916.91 g of sugars from hydrolyzed sugar beet pulp, with a maximum productivity of 18.06 g L−1h−1. Without interfering in the sugar production, ethanol, or lactic acid, it is also possible to produce pectin and phenolic compounds in the biorefinery. The lactic acid produced was purified by a bipolar membrane electrodialysis and the recovery reached 788.80 g/L with 98% w/w purity.
BioMed Research International, 2016
Sugar beet pulp, a byproduct of sugar beet processing, can be used as a feedstock in second-generation ethanol production. The objective of this study was to investigate the effects of pretreatment, of the dosage of cellulase and hemicellulase enzyme preparations used, and of aeration on the release of fermentable sugars and ethanol yield during simultaneous saccharification and fermentation (SSF) of sugar beet pulp-based worts. Pressure-thermal pretreatment was applied to sugar beet pulp suspended in 2% w/w sulphuric acid solution at a ratio providing 12% dry matter. Enzymatic hydrolysis was conducted using Viscozyme and Ultraflo Max (Novozymes) enzyme preparations (0.015-0.02 mL/g dry matter). Two yeast strains were used for fermentation: Ethanol Red (S. cerevisiae) (1 g/L) and Pichia stipitis (0.5 g/L), applied sequentially. The results show that efficient simultaneous saccharification and fermentation of sugar beet pulp was achieved. A 6 h interval for enzymatic activation between the application of enzyme preparations and inoculation with Ethanol Red further improved the fermentation performance, with the highest ethanol concentration reaching 26.9 ± 1.2 g/L and 86.5 ± 2.1% fermentation efficiency relative to the theoretical yield.
Journal on Processing and Energy in Agriculture
Lactic acid (LA) has gained considerable importance in the global market due to a wide range of applications. Because of the growing demand for food and feed, the use of lignocellulosic residues, by-products and waste streams is highly needed for commercial LA production. This study investigated the possibility of using potato stillage and sugar beet molasses for LA and biomass production by Lactobacillus paracasei NRRL B-4564 immobilized on sugar beet pulp. Adsorption of L. paracasei enabled easy separation of bacterial biomass from the fermentation media and its efficient reuse in three successive batch cycles. Total LA concentration of 146 g L-1 and average productivity of 1.03 g L-1 h-1 were achieved on waste substrate using bacterial cells immobilized on a natural carrier without mineral and nitrogen supplementation. The solid part of fermentation media remaining after LA fermentation is a valuable co-product, which could be used as animal feed rich in probiotic biomass.
Chemical Engineering Journal, 2012
In order to obtain solids extracts rich in hemicellulose from sugar beet pulp (SBP), an enzymatic depolymerization process with pectinolytic enzymes was evaluated. Both enzymatic preparations (Rohapect DA6L and Macer8 FJ) contributed to achieve rich fractions of hemicellulose; however Rohapect DA6L always showed a higher release of pectic oligosaccharides (pectin removal yield of 94.9%). The characterization of the obtained solid residue resulted in 30.6% hemicellulose, 25.95% cellulose, 12.1% lignin, 0.83% pectin and 4.86% protein. The total carbohydrates and reduced sugars in the hydrolysate were 143.5 and 5.24 g/L, respectively. The extracted pectin infrared spectrum revealed that it corresponds to low methoxyl pectin, confirmed by titrimetric method (DM: 56%). It can be stated that enzymatic treatment (with commercial pectinases) of SBP can be used in the recovery of valuable by-products, such as pectin oligosaccharides and solid fractions rich in hemicellulose.