title: Simultaneous Saccharification and Fermentation of Sugar Beet Pulp with Mixed Bacterial Cultures for Lactic Acid and Propylene Glycol Production.
abstract: Research into fermentative production of lactic acid from agricultural by-products has recently concentrated on the direct conversion of biomass, whereby pure sugars are replaced with inexpensive feedstock in the process of lactic acid production. In our studies, for the first time, the source of carbon used is sugar beet pulp, generated as a by-product of industrial sugar production. In this paper, we focus on the simultaneous saccharification of lignocellulosic biomass and fermentation of lactic acid, using mixed cultures with complementary assimilation profiles. Lactic acid is one of the primary platform chemicals, and can be used to synthesize a wide variety of useful products, including green propylene glycol. A series of controlled batch fermentations was conducted under various conditions, including pretreatment with enzymatic hydrolysis. Inoculation was performed in two sequential stages, to avoid carbon catabolite repression. Biologically-synthesized lactic acid was catalytically reduced to propylene glycol over 5% Ru/C. The highest lactic acid yield was obtained with mixed cultures. The yield of propylene glycol from the biological lactic acid was similar to that obtained with a water solution of pure lactic acid. Our results show that simultaneous saccharification and fermentation enables generation of lactic acid, suitable for further chemical transformations, from agricultural residues.
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. joanna.berlowska@p.lodz.pl.
authors.forename: Joanna
authors.initials: J
authors.lastname: Berlowska
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. weronikacieciura@wp.pl.
authors.forename: Weronika
authors.initials: W
authors.lastname: Cieciura
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. sebastian.borowski@p.lodz.pl.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Borowski
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. marta.dudkiewicz@p.lodz.pl.
authors.forename: Marta
authors.initials: M
authors.lastname: Dudkiewicz
authors.affiliation: Institute of General and Ecological Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland. michal.binczarski@p.lodz.pl.
authors.forename: Michal
authors.initials: M
authors.lastname: Binczarski
authors.affiliation: Institute of General and Ecological Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland. izabela.witonska@p.lodz.pl.
authors.forename: Izabela
authors.initials: I
authors.lastname: Witonska
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. anna.otlewska@p.lodz.pl.
authors.forename: Anna
authors.initials: A
authors.lastname: Otlewska
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Wolczanska 171/173, 90-924 Lodz, Poland. dorota.kregiel@p.lodz.pl.
authors.forename: Dorota
authors.initials: D
authors.lastname: Kregiel
mesh_terms: D061249:Batch Cell Culture Techniques; D027461:Beta vulgaris / Q000737:chemistry / Q000382:microbiology*; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D002241:Carbohydrates / Q000737:chemistry*; D005285:Fermentation; D019344:Lactic Acid / Q000096:biosynthesis*; D007778:Lactobacillus / Q000254:growth & development* / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry; D019946:Propylene Glycol / Q000378:metabolism*; D013395:Sucrose / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D010936:Plant Extracts; D019344:Lactic Acid; D013395:Sucrose; D019946:Propylene Glycol
keywords: Lactobacillus; assimilation profile; enzymatic hydrolysis; lactic acid; simultaneous fermentation; sugar beet pulp