Butanol Tolerance in a Selection of Microorganisms

National Renewable Energy Laboratory, National Bioenergy Center, Golden, CO 80401, USA.
Applied biochemistry and biotechnology (Impact Factor: 1.74). 05/2009; 153(1-3):13-20. DOI: 10.1007/s12010-008-8460-4
Source: PubMed


Butanol tolerance is a critical factor affecting the ability of microorganisms to generate economically viable quantities of butanol. Current Clostridium strains are unable to tolerate greater than 2% 1-butanol thus membrane or gas stripping technologies to actively remove butanol during fermentation are advantageous. To evaluate the potential of alternative hosts for butanol production, we screened 24 different microorganisms for their tolerance to butanol. We found that in general, a barrier to growth exists between 1% and 2% butanol and few microorganisms can tolerate 2% butanol. Strains of Escherichia coli, Zymomonas mobilis, and non-Saccharomyces yeasts were unable to surmount the 2% butanol growth barrier. Several strains of Saccharomyces cerevisiae exhibit limited growth in 2% butanol, while two strains of Lactobacillus were able to tolerate and grow in up to 3% butanol.

Download full-text


Available from: Eric P. Knoshaug, Jun 16, 2015
  • Source
    • "After incubation, the isolated colonies were inoculated into agar plate containing 1 to 5 % (v/v) butanol concentration. Several rounds of screening were performed to purify and to isolate strains with high butanol tolerance [1]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Due to a limited supply of petroleum oils, microbial production of butanol has gained more attention in recent years. However, major road blocks of the current butanol fermentation were low yield, low productivity and most importantly low titer due to the toxicity of butanol to their producing strains. In our current research efforts were made to evaluate the potential butanol tolerance bacterial strains for its possible role as a host for butanol production. Among the thirty screened bacterial strains, only few showed tolerance towards butanol in which AS2 I has the capability to tolerate upto 5 % butanol at 72 h with 30 % of cell growth. Assays for different enzymes involved in butanol production were also carried out. from the present study showed that the best butanol tolerant bacteria was found to be Paneibacillus sp. using 16S rDNA sequencing and had enhanced activity of butanol tolerance enzymes. Overall results shows that the strain AS2 I can be engineered as promising host for enhanced butanol production.
  • Source
    • "One of the biggest problems faced by the industry is the low butanol tolerance exhibited by most microorganisms. While ethanol-producing organisms such as S. cerevisiae can tolerate ethanol concentrations close to 20% v/v, butanol producers are generally limited to 2-3% v/v [Knoshaug & Zhang (2009)]. This leads to increased downstream separation costs and larger production equipment. "
    [Show abstract] [Hide abstract]
    ABSTRACT: It has now been established that extremophiles and their enzymes will likely play important roles in many kinds of bioprocessing e.g., in conversion of nonfood biomass into biofuels, including bioethanol, biobutanol, and biogas; bioremediation of contaminated aquifers; and pharmaceuticals. Extremophiles, which can grow under extreme conditions of temperature, acidity, alkalinity, or salinity, have been reported to produce biofuels and valued added products of unique properties. The processes employing extremophilic microorganisms to produce biofuels and value added products are cost effective, more economical, having low risk of unwanted microbial contamination, increased reaction kinetics, higher yields of products, and minimal environmental hazards. This chapter presents state-of-the-art review and performs in-depth analysis of the biofuels (e.g., bioethanol, biobutanol, biodiesel, biogas) and value added products (e.g., polyhydroxy alkanoates, exopolysaccharides) production using extremophiles. In addition, existing technologies of biofuel production and their limitations and strategies to overcome those limitations are discussed.
    Advances in Biotechnology, 01/2015: chapter 2: pages 17-51; I.K. International Publishing House New Delhi., ISBN: 978-93-84588-09-0
  • Source
    • "Butanol tolerance was checked in MSA plates containing 1 to 5 % (v/v) butanol with the above said conditions. Several rounds of screening were performed to purify and isolate strains with high butanol tolerance (Sardssai and Bhosle, 2002; Knoshaug et al., 2009). The isolated strain was stored at -20 °C for further use. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Butanol tolerance is a complex mechanism affecting the ability of microorganisms to generate economically viable quantities of butanol. The objective of this study was to isolate and characterize butanol tolerant bacterial strains which can act as potential alternative hosts for butanol production. The potential bacterial isolates were screened, based on the non toxic effect on cell growth rate and degradation ability of sago waste which was used as a sole carbon source with butanol enrichment. During this study, it was found that a growth barrier existed between 1 to 5 % butanol concentrations and only few selected isolates could tolerate upto 5% butanol after long term adaptation. Screening of five isolates proved to be more tolerant, which were identified as Bacillus megaterium, B. aryabhattai, B. tequilensis, and B. circulans using 16S rDNA sequence. These isolates were markedly attractive to identify butanol tolerance specific stress response genes and furtherengineered to actas a genetic hostfor biobutanol production.
    Journal of Environmental Biology 11/2014; 35(6). · 0.56 Impact Factor
Show more