Production of High Levels of Chirally Pure d-2,3-Butanediol with a Newly Isolated Bacillus Strain

Abstract

2,3-Butanediol (2,3-BD), especially when it exists in the chirally pure form, is a valuable chemical feedstock with numerous applications in various industries. However, in most cases, the 2,3-BD naturally produced by the microorganism is a mixture of two of the three isomers (d-2,3-BD, l-2,3-BD, and meso-2,3-BD), which has restricted applications and thus a much lower value than the chirally pure one. In this study, we report a new isolate Bacillus spp. FJ-4 strain, which can produce highly chirally pure d-2,3-BD (>99.9%) to high levels, with very high productivity and yield. The composition of the fermentation medium for the strain was sequentially optimized using statistical experimental methodologies. During a fed-batch experiment, 100.0 g/L of d-2,3-BD was produced from 226.8 g/L glucose, with a yield of 0.44 g/g (88.2% of the theoretical maximum). Acetoin was the primary byproduct, and no other byproduct such as lactate, acetate, or ethanol was detected, which would be advantageous for the downstream purification process. Moreover, no special conditions such as limited oxygen level (which generally limits the cell growth and thus final d-2,3-BD production) are required for the fermentation. These results indicated that Bacillus spp. FJ-4 is a robust workhorse for efficient d-2,3-BD production from low-value carbon sources.

Process optimization for mass production of 2,3-butanediol by Bacillus subtilis CS13

“…The previous study found that oxygen supply favors the high-level production of 2,3-BD [11]. Besides, the type of substrate and concentration, nitrogen source, and inorganic salts also significantly affect the 2,3-BD formation [11][12][13][14]. Recently, genetic engineering methods have been widely used to reduce the synthesis of byproducts and increase 2,3-BD production [15,16].…”

Recruiting Energy-Conserving Sucrose Utilization Pathways for Enhanced 2,3-Butanediol Production in Bacillus subtilis

“…They were all confirmed as B. subtilis strains through the analysis of their 16S rDNA gene sequence (data not shown) . As a starting point, first, the six newly isolated strains along with the 168 strain (the type strain of B.…”

“…B. subtilis N-3, N-5, N-6, A-1, FJ-1 and FJ-2 strains were newly isolated from fermented foods (Chinese natto and sufu from the local grocery store) as described previously . 2,3-BD fermentations were carried out using the 2,3-BD fermentation medium (containing 117.3 g/L sucrose; 15 g/L yeast extract; 3 g/L tryptone; 3 g/L NaCl; 3 g/L (NH 4 ) 2 SO 4 ; 0.6 g/L MgSO 4 ; 1 mM FeSO 4 ; 1 mM CaCl 2 ; 1 mM MnSO 4 and 1 mM ZnCl 2 ) in 250 mL shaking flasks at 37 °C and 150 rpm for 120 h. When sugar cane juice was used as the feedstock, two times diluted sugar cane juice (contains 91.7 g/L sucrose, 11.9 g/L glucose, 8.9 g/L fructose) was used to replace the sucrose in the 2,3-BD fermentation medium.…”

Bioprocess Development for 2,3-Butanediol Production from Crude Glycerol and Conceptual Process Design for Aqueous Conversion into Methyl Ethyl Ketone

“…Microbial BDO production has been widely under investigation as a more sustainable process than chemical synthesis. However, the high cost of commercial sugars and downstream separation and purification (DSP) of BDO are serious drawbacks for industrial implementation. , The utilization of crude glycerol could reduce BDO production costs if high fermentation efficiency is achieved and synthetic fermentation media are used . Yang et al reported a high BDO concentration of 102.3 g/L under fed-batch mode using crude glycerol supplemented with molasses.…”