Butanol tolerance of carboxydotrophic bacteria isolated from manure composts

Abstract

Carboxydotrophic bacteria (carboxydotrophs) have the ability to uptake carbon monoxide (CO) and synthesize butanol. The aims of this study were to determine the butanol tolerance and biological production of butanol carboxydotrophic strains. In this study, 11 carboxydotrophic strains were exposed to increasing n-butanol concentrations (1-3% vol/vol) to determine their effect on growth. Butanol production by the strains was quantified and the identity of the strains was elucidated using 16S rRNA sequencing. The carboxydotrophic strains possessed inherent tolerance to butanol and tolerated up to 3% n-butanol. Among the 11 strains, T1-16, M2-32 and M3-28 were the most tolerant to butanol. The 16S rRNA gene sequence of these strains was similar (99% nucleotide similarity) to the butanol-tolerant strains Bacillus licheniformis YP1A, Pediococcus acidilacti IMUA20068 and Enterococcus faecium IMAU60169, respectively. The carboxydotrophic strains screened in this study have two distinct features: (1) high tolerance to butanol and (2) natural production of low concentration of butanol from CO, which distinguish them from other screened butanol-tolerant strains. The butanol tolerance of these carboxydotrophic strains makes them ideal for genetic studies, particularly the molecular mechanisms that enable them to survive such hostile environmental conditions and the identification of genes that confer tolerance to butanol.

The Biotic and Abiotic Carbon Monoxide Formation During Aerobic Co-digestion of Dairy Cattle Manure With Green Waste and Sawdust

“…Lee et al (2012) speculated that trace gas release from aerobic waste degradation might be due to thermal excitation of organic functional groups by lowering the barrier to reactivity with reactive oxidized species (ROS) or simple thermal decomposition. On the other hand, CO is an energy source in anaerobic conditions for many bacteria with the genus Carboxydotrophic (Pomaranski and Tiquia-Arashiro, 2016). Both of these processes lead to a reduction in CO concentration in the decomposed material.…”

“…An example of respiratory metabolism is the oxidation of CO, coupled with O 2 reduction (Gullotta et al, 2012). Bacteria of the Carboxydotrophic genus, which are aerobic microbes, use CO as a source of C and energy (Pomaranski and Tiquia-Arashiro, 2016). They transfer electrons from CO dehydrogenase (CODH) by catalyzing the oxidation of CO through the respiratory chain, which eventually reduces oxygen.…”

Low cell surface hydrophobicity is one of the key factors for high butanol tolerance of Lactic acid bacteria

“…bulgaricus strains retaining 30% relative growth rate at 3%, and capable to grow at 4% butanol were isolated. The growth at 3% butanol obtained for P. acidilactici DF3 (55.7% relative growth rate) is the highest reported to date and place the species among the most butanol‐resistant bacteria isolated so far . Some of the novel strains reported here could be used as microbial cell factories for butanol production and as a valuable genetic resource for strains improvement.…”

“…However, its biotechnological production will not be possible in industrial scale, until the problem of low microbial tolerance to butanol is solved. Over the last decade, a number of scientific studies are devoted to tolerance enhancement of both the “classical producers” of genus Clostridium , as well as the engineered non‐natural butanol producing strains . In a recent review, Peabody and Kao (2016) categorized the tools utilized for butanol tolerance development into several groups: the use of genomic libraries and adaptive laboratory evolution; analyses of regulatory, proteomic, and metabolic cellular responses; an implementation of known mechanisms; and the use of advanced cellular modelling .…”

“…Good model organisms to study these effects are the representatives of Lactic acid bacteria (LAB) by two main reasons. First, a number of highly butanol resistant strains of LAB were recently reported: Lactobacillus brevis , Enterococcus faecium , Ent. faecalis , Pediococcus acidilactici , P. pentosaceus , Lb.…”