Showing papers on "2,3-Butanediol published in 2009"

In situ recovery of 2,3-butanediol from fermentation by liquid–liquid extraction

Abstract: End-product conversion, low product concentration and large volumes of fermentation broth, the requirements for large bioreactors, in addition to the high cost involved in generating the steam required to distil fermentation products from the broth largely contributed to the decline in fermentative products. These considerations have motivated the study of organic extractants as a means to remove the product during fermentation and minimize downstream recovery. The aim of this study is to assess the practical applicability of liquid-liquid extraction in 2,3-butanediol fermentations. Eighteen organic solvents were screened to determine their biocompatibility, and bioavailability for their effects on Klebsiella pneumoniae growth. Candidate solvents at first were screened in shake flasks for toxicity to K. pneumoniae. Cell density and substrate consumption were used as measures of cell toxicity. The possibility of employing oleyl alcohol as an extraction solvent to enhance end product in 2,3-butanediol fermentation was evaluated. Fermentation was carried out at an initial glucose concentration of 80 g/l. Oleyl alcohol did not inhibit the growth of the fermentative organism. 2,3-Butanediol production increased from 17.9 g/l (in conventional fermentation) to 23.01 g/l (in extractive fermentation). Applying oleyl alcohol as the extraction solvent, about 68% of the total 2,3-butanediol produced was extracted.

Enhanced pyruvate to 2,3-butanediol conversion in lactic acid bacteria

Abstract: A high flux of metabolites from pyruvate to 2,3-butanediol in Lactobacillus plantarum was achieved through genetic engineering. Substantial elimination of lactate dehydrogenase activity in the presence of heterologously expressed butanediol dehydrogenase activity led to 2,3 butanediol production that was at least 49% of the total of major pyruvate-derived products.

Extractive Capacity of Oleyl Alcohol on 2, 3-Butanediol Production in Fermentation Process with Use of Klebsiella pneumoniae PTCC 1290

Abstract: Recovery of metabolites from fermentation broth by solvent extraction can be used to optimize fermentation processes. End-product reutilization, low product concentration and large volumes of fermentation broth and the requirements for large bioreactors, in addition to the high cost largely contributed to the decline in fermentative 2,3-butanediol production. Extraction can successfully be used for in-situ alcohol recovery in 2,3-butanediol fermentations to increase the substrate conversion. In the present work organic extraction of 2,3-butanediol produced by Klebsiella pneumoniae fermentation was studied to determine solvent effect on 2,3-butanediol production. The aim of this project was liquid-liquid extractive fermentation systems evaluation as an alternative to overcome the end product effect and to increase of 2,3-butanediol production by K.pneumoniae because Conventional fermentative production of 2,3-butanediol by K. pneumoniae has the disadvantage of product reutilization by the organism. Alternatives to overcome this problem have met with limited success. Extractive fermentation has been shown to solve this problem. An effort has been made in this study to use for the extractive fermentation of 2,3-butanediol using oleyl alcohol as extract-ant. Eighteen organic solvents were examined to determine their biocompatibility for in situ extraction of fermentation products from cultures of the K. pneumoniae. From 18 tested solvents, 13 of which were non-toxic to K.pneumoniae. The highest 2,3-butanediol production (23.01 g l -1 ) was achieved when oleyl alcohol was used. In situ removal of end products from K.pneumoniae resulted in increased productivity. In conclusion 2,3-butanediol productivity increased from 0.5 g l -1 h -1 to 0.66 g l -1 h -1 in extractive fermentation using oleyl alcohol as the extraction solvent.

Fermentation and salting-out Separation of 2,3-butanediol

Abstract: The bioconversion of 2,3-butanediol by Klebsiella pneumoniae CICC 10011 was studied with a medium based on glucose in fed-batch fermentations,and the salting out separation was explored.The final concentration of 2,3-butanediol and acetoin in the fermentation broth reached 90.98 g/L and 12.40 g/L,respectively.The molar yield of butanediol was 82.7% and the productivity was 2.1 g/(L·h).The effects of concentration cycles and salt concentrations on the extraction of 2,3-butanediol in flocculated broth were also studied.When the fermentation broth was concentrated to 70%,45% K2HPO4 was added,the partition coefficients and the recovery rate of 2,3-butanediol and acetoin reached 9.10,and 79.37%,respectively.The concentration of 2,3-butanediol in top phase reached 420 g/L,the partition coefficient and the recovery rate reached 11.9 and 83.48%.Results indicate that the process has advantages of simple,energy saving,and good potential for application.

Production of 2,3-butanediol from fermentation of xylose by Klebsiella oxytoca ZU-03.

Abstract: The production of 2,3-butanediol was carried out from fermentation of xylose by Klebsiella oxytoca ZU-03,in which xylose was the main reducing sugar in hemicellulosic hydrolysate.Under optimized conditions: xylose mass concentration 90 g/L,corn liquor mass concentration 6 g/L,inoculum 10 %(volume fraction),initial pH value 5.5 and 30 ℃,concentration of 2,3-butanediol reached 36.22 g/L and yield of 2,3-butanediol from xylose was 0.45 g/g.

A method for co-production of 1, 3-propanediol, 2,3-butanediol and polyhydroxypropionic acid by fermentation of constructed genetic engineering bacteria

Abstract: A method for co-production of 1,3-propanediol (PDO), 2,3-butanediol (BDO) and polyhydroxypropionic acid (PHP) via fermentation by genetic engineering bacteria comprises the following steps of: knocking out D type lactate dehydrogenase from wild PDO producing bacteria, introducing coenzyme A depending aldehyde dehydrogenase and polyhydroxy fatty acid synthase genes, constructing genetic engineering bacteria for producing PDO, BDO and PHP; fermenting aerobically and adjusting fermentation by adding mixture flow of glycerin and base solution; filtering fermentation broth by membrane, treating it by electrodialysis, concentrating, rectifying which separates PDO, BDO and PHP. The said genetic engineering bacteria can produce PDO, BDO and PHP at the same time, which increases utilization ratio of raw material, reduces cost, decreases generation of byproduct lactate, simplifies post extraction technique, lowers extraction cost, and increases generation of nicotinamide adenine dinucleotide 2 (NADH 2 ) while PHP is introduced.

Fermentation of 2,3-Butanediol Using Saccharified Hydrolyzate from Dioscorea zingiberensis

Abstract: The fed-batch fermentation of 2,3-butanediol by Klebsiella pneumoniae from Dioscorea zingiberensis was investigated.The concentration and productivity of target products, organic acid metabolism and glucose metabolic flux distributions during the fermentation were analyzed.The results showed that organic acids in Dioscorea zingiberensis could promote metabolic flux in tricarboxylic acids cycle and acetic acid production pathway and decrease the butane diacid production pathway, thus, 2,3-butanediol production was increased.80.20 g/L of 2,3-butanediol, 86.19 g/L of 2,3-butanediol and acetoin, corresponding to 1.54 g/(L-h) of productivity, were obtained using the hydrolyzate of Dioscorea zingiberensis as substrate and feeding glucose during fed-batch fermentation, which increased 8.50%, 7.38% and 7.69%, respectively, compared with that using glucose as sole substrate.

Study on 2,3-Butanediol Production by Serratia Marcescens Using Sucrose and Ammonium Citrate

Abstract: Effects of several inorganic nitrogen sources on biomass and 2,3-butanediol production by Serratia marcescens were studied. The results showed that ammonium citrate was the optimum inorganic nitrogen source. Based on the previous experiments,ammonium citrate and manganese sulfate were studied by response surface methodology to determine the optimized concentration. The optimal medium was used to perform shaking fermentation and fed-batch fermentation experiments. Ultimately,the strain converted 110 g·L-1 sucrose to 44 g·L-1 2,3-butanediol,and the transformation efficiency and productivity were 0.4 g·g-1 and 1.13 g·L-1·h-1 respectively in shaking flasks. In fed-batch fermentation,a 2,3-butanediol level of 81.2 g·L-1 and acetoin level of 7.7 g·L-1 were obtained from 166 g·L-1 sucrose,and the transformation efficiency and productivity of 2,3-butanediol achieved to 0.489 g·g-1 and 1.7 g·L-1·h-1,respectively.

Optimization of Cofermentation of Glucose and Xylose for Sythesis of 2,3-Butanediol

Abstract: The production conditions of 2,3-butanediol by Klebsiella pneumoniae XJ-Li from glucose and xylose were optimized, and the regulation methods for 2,3-butanediol fermentation were also determined based on the metabolic features of hexose and pentose.The results displayed that suitable culture conditions were defined as glucose of 60 g/L, xylose of 40 g/L, ammonium dihydrogen phosphate of 5.75 g/L and pH of 5.5, and the concentration of 2,3-butanediol reached 19.24 g/L under the conditions when the strain was cultured at 38℃.The yield of 2,3-butanediol was increased by 16.4% after maintaining the pH about 5.5 in the fermentation process.And 60 mg/L of vitamin C was added into medium to regulate the redox state of system, which made the yield of 2,3-butanediol improved by 44.3% of 2,3-butanediol fermentation.33.47 g/L of 2,3-butanediol was obtained in batch fermentation for 48 h under optimum culture conditions.