Enhancing Butanol Production under the Stress Environments of Co-Culturing Clostridium acetobutylicum/Saccharomyces cerevisiae Integrated with Exogenous Butyrate Addition

Abstract

In this study, an efficient acetone-butanol-ethanol (ABE) fermentation strategy integrating Clostridium acetobutylicum/Saccharomyces cerevisiae co-culturing system with exogenous butyrate addition, was proposed and experimentally conducted. In solventogenic phase, by adding 0.2 g-DCW/L-broth viable S. cerevisiae cells and 4.0 g/L-broth concentrated butyrate solution into C. acetobutylicum culture broth, final butanol concentration and butanol/acetone ratio in a 7 L anaerobic fermentor reached the highest levels of 15.74 g/L and 2.83 respectively, with the increments of 35% and 43% as compared with those of control. Theoretical and experimental analysis revealed that, the proposed strategy could, 1) extensively induce secretion of amino acids particularly lysine, which are favorable for both C. acetobutylicum survival and butanol synthesis under high butanol concentration environment; 2) enhance the utilization ability of C. acetobutylicum on glucose and over-produce intracellular NADH for butanol synthesis in C. acetobutylicum metabolism simultaneously; 3) direct most of extra consumed glucose into butanol synthesis route. The synergetic actions of effective amino acids assimilation, high rates of substrate consumption and NADH regeneration yielded highest butanol concentration and butanol ratio in C. acetobutylicum under this stress environment. The proposed method supplies an alternative way to improve ABE fermentation performance by traditional fermentation technology.

Artificial consortium that produces riboflavin regulates distribution of acetoin and 2,3‐butanediol by Paenibacillus polymyxa CJX518

“…S6). Although it was obvious, we were still unclear as to whether recombinant E. coli could really survive and whether it performed metabolic functions after P. polymyxa was inoculated into the coculture . Therefore, it was very necessary to investigate the viability of recombinant E. coli cells.…”

“…Normally, the single colonies of P. polymyxa were white colored on LB plates, while the color was yellow around the single colonies of recombinant E. coli , which produces VB 2 on LB plates. The colony‐forming units (CFU) on each plate represented the number of recombinant E. coli . The appearance of CFUs proved the cell viability of E. coli .…”

“…During the Chinese Maotai‐flavor liquor‐making process, a coculture of S. cerevisiae and B. licheniformis improves the generation of flavor through metabolism , indicating that flavor producers and microbial interaction regulators are important for the inoculated fermentation of Chinese sesame‐flavored liquor . It has been demonstrated that a coculture of C. acetobutylicum and S. cerevisiae can enhance butanol concentrations by the synergetic actions of effective amino acid assimilation, high rates of substrate consumption, and NADH regeneration .…”

Transcriptional analysis of amino acid, metal ion, vitamin and carbohydrate uptake in butanol-producing Clostridium beijerinckii NRRL B-598

“…While some clostridial strains are able to utilize a wide range of carbohydrates other than glucose, they still need growth factors such as vitamins and trace elements for growth and metabolite production. Many researchers have reported that addition of appropriate concentrations of amino acids and metal ions to the cultivation medium stimulate bacterial growth and result in increased solvent yield [7–10]. Therefore, an in-depth understanding of transport and metabolism of amino acids, sugars, vitamins and metal ions is important for the selection of proper and inexpensive substrates for ABE fermentation and can potentially result in a decreased solvent price [11,12].…”

Enhanced Biobutanol Production in Folic Acid-Induced Medium by Using Clostridium acetobutylicum NRRL B-527

“…11 Additionally, few amino acids that are either self-generated or exogenously incorporated, enhance the cell’s survival rate and butanol synthesis. 12…”