Enhanced Butanol Production by Clostridium beijerinckii BA101 Grown in Semidefined P2 Medium Containing 6 Percent Maltodextrin or Glucose

Abstract

Dramatically elevated levels of butanol and acetone resulted in higher butanol and total solvent yields for hyperamylolytic Clostridium beijerinckii BA101 relative to the NCIMB 8052 parent strain grown in semidefined P2 medium containing either 6% glucose or STAR-DRI 5 maltodextrin. C. beijerinckii BA101 consistently produced on the order of 19 g of butanol per liter in 20-liter batch fermentations. This represents a greater than 100% increase in butanol concentration by the BA101 strain compared to the parent NCIMB 8052 strain. The kinetics of butanol production over time also indicate a more rapid rate of butanol production by BA101 in semidefined P2 medium containing glucose or maltodextrin. The lower levels of butyric and acetic acids produced over the course of the fermentation carried out by BA101 are consistent with an enhanced capacity for uptake and recycling of these acids. C. beijerinckii BA101 appears to more completely utilize carbohydrate compared to the 8052 strain. Carbon balance following fermentation by C. beijerinckii 8052 and BA101 indicates that sufficient carbon is available for the twofold increase in butanol concentration observed during BA101 fermentations. C. beijerinckii BA101 also has superior solvent production capacity during continuous culture fermentation in P2 medium containing 6% glucose. Volumetric solvent yields of 0.78 and 1.74 g/liter/h for BA101 and 0.34 and 1.17 g/liter/h for NCIMB 8052 were obtained at dilution rates of 0.05 and 0.20 h ؊1 , respectively. No drift towards acid synthesis (strain degeneration) was observed for up to 200 h (d ‫؍‬ 0.05 h ؊1) and 100 h (d ‫؍‬ 0.20 h ؊1).

Genomic, Transcriptional, and Phenotypic Analysis of the Glucose Derepressed Clostridium beijerinckii Mutant Exhibiting Acid Crash Phenotype

“…In particular, on mannose, BA105 demonstrated significant amounts of solvent production over 20 g L À1 , that is similar to BA101 mutant well known for hyper-butanol producing strain. [7] Although glucokinase could be responsible for the phenotypic change of BA105, it is still unclear whether the mutation in the glucokinase gene of BA105 affected its regulatory function or the enzyme activity. A further study focusing on sugar transport needs to be performed to confirm the effect of the glucokinase mutation on sugar utilization in C. beijerinckii.…”

“…[3] However, the BA105 mutant has not been further characterized or used for butanol production, while the BA101 mutant that was developed at the same time has been widely studied and known as a hyper-solvent producing mutant. [3,[7][8][9][10] The previous study reported that the enhanced amylolytic activity correlated with higher butanol production in C. beijerinckii. [2,3] Therefore, we revisited BA105 mutant to test its potential ability to overproduce butanol in this study.…”

Fermentative butanol production by clostridia

“…C. beijerinckii BA101 has an altered acid-to-solvent switching mechanism and produces butanol during the exponential phase (Formanek et al, 1997). Although the initial levels of acids produced by C. beijerinckii BA101 are similar to its parental strain, the levels decrease dramatically during solventogenesis.…”

“…Many industrial strains have been generated by random mutation and subsequent selection. The C. beijerinckii BA101 strain was generated by treating C. beijerinckii NCIMB 8052 with a mutagen N-methyl-N9-nitro-N-nitrosoguanidine and selectively enriching the candidate mutants on the nonmetabolizable glucose analog 2-deoxyglucose (Formanek et al, 1997). C. beijerinckii BA101 is able to produce twofold more butanol and acetone than its parent strain and has distinct fermentation characteristics.…”

Butanol production from sweet sorghum bagasse with high solids content: Part I—comparison of liquid hot water pretreatment with dilute sulfuric acid

“…During the last 40 years, fluctuations (both rise and fall) in gasoline prices encouraged researchers around the world to focus on the development of novel microbial strains and fermentation processes to make production of this biofuel economically viable. [1][2][3][4][5][6][7][8][9][10][11][12] Butanol can be produced from sugars such as glucose, sucrose, and lactose in a two step process (fermentation 1 distillative recovery). The microbial strains such as Clostridium beijerinckii, C. acetobutylicum, or C. saccharobutylicum can produce enzymes that hydrolyze disaccharide sugars (sucrose and lactose) into monomeric sugars followed by fermentation to butanol.…”