1,3-Propanediol production from crude glycerol by Clostridium butyricum DSP1 in repeated batch

Abstract

Background: The production of biofuels from renewable energy sources is one of the most important issues in industrial biotechnology today. The process is known to generate various by-products, for example crude glycerol, which is obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including microbial conversion to 1,3-propanediol (1,3-PD), a raw material for the synthesis of polyesters and polyurethanes. Results: The paper presents results of a study on the synthesis of 1,3-propanediol from crude glycerol by a repeated batch method with the use of Clostridium butyricum DSP1. Three cycles of fermentation medium replacement were carried out. The final concentration of 1,3-PD was 62 g/L and the maximum productivity, obtained during the second cycle, reached 1.68 g/L/h. Additionally, experiments conducted in parallel to the above involved using the entire quantity of the culture broth removed from the bioreactor to inoculate successive portions of fermentation media containing crude glycerol at concentrations of 80 g/L and 100 g/L. Under those conditions, the maximum 1,3-PD concentrations were 43.2 g/L and 54.2 g/L. Conclusions: The experiments proved that by using a portion of metabolically active biomass as inoculum for another fermentation formula it is possible to eliminate the stage of inoculum growth and thereby reduce the length of the whole operation. Additionally, that strategy avoids the phase of microbial adaptation to a different source of carbon such as crude glycerol, which is more difficult to utilize, thus improving the kinetic parameters of 1,3-PD production.

Biohydrogen production by co-fermentation of crude glycerol and apple pomace hydrolysate using co-culture of Enterobacter aerogenes and Clostridium butyricum

“…The purpose of this study was to evaluate the hydrogen production potential of crude glycerol when co-fermented with apple pomace hydrolysate at different inoculum size and to increase substrate utilization rate with reduced 1,3-PD and ethanol formation. Since CG can cause 66% of substrate inhibition (Viana et al, 2012; Szymanowska-Powałowska, 2014), the concept of co-substrate addition deals with such inhibition and will allow the process to run at higher substrate concentration. An integrated co-substrate technique opens up opportunity in coming years to use mixtures of various kinds of organic wastes to increase the H 2 production.…”

“…The higher reduction state of glycerol needs excess of reducing equivalents, which can be accomplished by diverting NADH consuming pathway towards reduced or neutral end-products (ethanol or 1,3-PD) or via H 2 production (Heyndrickx et al, 1991). Research carried out using the Enterobacter and Clostridium with crude glycerol as substrate either produced ethanol (Ito et al, 2005;Jitrwung and Yargeau, 2011;Nwachukwu et al, 2012;Nwachukwu et al, 2013) or 1,3-propanediol (Zeng, 1996;Gonzalez-Pajuelo et al, 2004;Gonzalez-Pajuelo et al, 2005;Chatzifragkou et al, 2011;Szymanowska-Powałowska, 2014), which needs to be produced at higher concentration at the expense of media cost (Jitrwung and Yargeau, 2011). Additionally a co-culture of facultative (Enterobacter aerogenes) and strict anaerobe (Clostridium butyricum) can ensure high H 2 yield by using glucose as carbon source in the absence of expensive reducing agent (Yokoi et al, 1998;Phowan et al, 2010).…”

Biorefinery for Glycerol Rich Biodiesel Industry Waste

“…Metabolically active bacterial biomass acclimatized during fermentation were used to inoculate subsequent bioreactors having CG (80 and 100 g/L). Here, the maximum 1,3-PD concentrations achieved were 43.2 and 54.2 g/L, respectively [25]. Genetically modified Escherichia coli strain carrying dhaB1 and dhaB2 (encoding for vitamin B12 independent glycerol dehydratase and its activator, respectively) from C. butyricum along with E. coli yqhD gene (encoding for 1,3-PDO oxidoreductase isoenzyme, YqhD) gave a 1,3-PDO yield of 104.4 g/L and a productivity of 2.61 g/L/h from glycerol as C source [26].…”

Produção biotecnológica de produtos de valor agregado utilizando glicerol residual proveniente da síntese de biodiesel

“…25 Vários estudos relata m a possível inibição do processo por baixos valores de pH, em decorrência da síntese de ácidos orgânicos de acordo com a via metabólica, indicando a importância do desenvolvimento de uma estratégia de controle de pH adequado para melhorar a produção de 1,3-PDO. 9,32,28,22 Por meio do controle de pH apropriado (mantido a um valor de 7,0) e utilizando estirpes de Klebsiella oxytoca (FMCC-197), a partir da mesma quantidade inicial do glicerol em bruto, um estudo duplicou a massa final de concentração em volume de 1,3-PDO, com a obtenção de um rendimento 29% maior e redução do tempo de fermentação de 96 para 32h.…”

“…32,21 A concentração final de 1,3-propanodiol obtida depende também da natureza e da concentração do substrato, sendo a utilização do glicerol puro geralmente o responsável pelo rendimento e pela produtividade ligeiramente mais baixos. 13 A presença de glicerol residual no meio leva ao crescimento de biomassa mais elevado, fenômeno que pode ser atribuído à presença de fosfatos e seus sais em glicerol em bruto, resultando em efeito tampão de pH nas fases iniciais da fermentação.…”