Enhanced Biobutanol Production in Folic Acid-Induced Medium by Using Clostridium acetobutylicum NRRL B-527.

The conventional acetone-butanol-ethanol fermentation process suffers from several key hurdles viz. low solvent titer, insufficient yield and productivity, and solvent intolerance which largely affect butanol commercialization. To counteract these issues, the effect of stimulator, namely, folic acid was investigated in the present study to improve butanol titer. Folic acid is involved in biosynthesis of a diverse range of cellular components, which subsequently alter the amino acid balance. Therefore, different concentrations of folic acid were screened, and 10 mg/L supplementation resulted in a maximum butanol production of 10.78 ± 0.09 g/L with total solvents of 18.91 ± 0.21 g/L. Folic acid addition at different time intervals was also optimized to get additional improvements in final butanol concentration. Overall, folic acid supplementation resulted in two-fold increase in butanol concentration and thus could be considered as a promising strategy to enhance solvent titers.

Strategic intensification in butanol production by exogenous amino acid supplementation: Fermentation kinetics and thermodynamic studies.

Amino acids are vital precursors in many biochemical production pathways in addition to efficient nitrogen source which could enhance microbial growth yields. Therefore, in present study, the effect of amino acids from aliphatic and aromatic family was comprehensively evaluated in batch and integrated fed batch fermentation system. Clostridium acetobutylicum NRRL B-527 was able to utilize 54.15 ±â€¯1.0 g/L glucose to produce 12.43 ±â€¯0.10 g/L butanol under batch cultivation. Interestingly, a significant step up in butanol titer (20.82 ±â€¯0.33 g/L) was achieved by using fed-batch fermentation process integrated with liquid-liquid extraction module. Besides, mathematical modeling studies demonstrated the best fitting of experimental data with first order reaction kinetics. Overall, an enhancement in solvent titer by induction of essential cellular components coupled with advance bioprocess strategy was successfully utilized in this study for its further applications.

Role of Trace Elements as Cofactor: An Efficient Strategy toward Enhanced Biobutanol Production.

Metabolic engineering has the potential to steadily enhance product titers by inducing changes in metabolism. Especially, availability of cofactors plays a crucial role in improving efficacy of product conversion. Hence, the effect of certain trace elements was studied individually or in combinations, to enhance butanol flux during its biological production. Interestingly, nickel chloride (100 mg L-1) and sodium selenite (1 mg L-1) showed a nearly 2-fold increase in solvent titer, achieving 16.13 ± 0.24 and 12.88 ± 0.36 g L-1 total solvents with yields of 0.30 and 0.33 g g-1, respectively. Subsequently, the addition time (screened entities) was optimized (8 h) to further increase solvent production up to 18.17 ± 0.19 and 15.5 ± 0.13 g L-1 by using nickel and selenite, respectively. A significant upsurge in butanol dehydrogenase (BDH) levels was observed, which reflected in improved solvent productions. Additionally, a three-dimensional structure of BDH was also constructed using homology modeling and subsequently docked with substrate, cofactor, and metal ion to investigate proper orientation and molecular interactions.

Cauliflower waste utilization for sustainable biobutanol production: revelation of drying kinetics and bioprocess development.

Efficient yet economic production of biofuel(s) using varied second-generation feedstock needs to be explored in the current scenario to cope up with global fuel demand. Hence, the present study was performed to reveal the use of cauliflower waste for acetone-butanol-ethanol (ABE) production using Clostridium acetobutylicum NRRL B 527. The proximate analysis of cauliflower waste demonstrated to comprise 17.32% cellulose, 9.12% hemicellulose, and 5.94% lignin. Drying of cauliflower waste was carried out in the temperature range of 60-120 °C to investigate its effect on ABE production. The experimental drying data were simulated using moisture diffusion control model. The cauliflower waste dried at 80 °C showed maximum total sugar yield of 26.05 g L-1. Furthermore, the removal of phenolics, acetic acid, and total furans was found to be 90-97, 10-40, and 95-97%, respectively. Incidentally, maximum ABE titer obtained was 5.35 g L-1 with 50% sugar utilization.

New Insight into Sugarcane Industry Waste Utilization (Press Mud) for Cleaner Biobutanol Production by Using C. acetobutylicum NRRL B-527.

In the present study, press mud, a sugar industry waste, was explored for biobutanol production to strengthen agricultural economy. The fermentative production of biobutanol was investigated via series of steps, viz. characterization, drying, acid hydrolysis, detoxification, and fermentation. Press mud contains an adequate amount of cellulose (22.3%) and hemicellulose (21.67%) on dry basis, and hence, it can be utilized for further acetone-butanol-ethanol (ABE) production. Drying experiments were conducted in the temperature range of 60-120 °C to circumvent microbial spoilage and enhance storability of press mud. Furthermore, acidic pretreatment variables, viz. sulfuric acid concentration, solid to liquid ratio, and time, were optimized using response surface methodology. The corresponding values were found to be 1.5% (v/v), 1:5 g/mL, and 15 min, respectively. In addition, detoxification studies were also conducted using activated charcoal, which removed almost 93-97% phenolics and around 98% furans, which are toxic to microorganisms during fermentation. Finally, the batch fermentation of detoxified press mud slurry (the sample dried at 100 °C and pretreated) using Clostridium acetobutylicum NRRL B-527 resulted in a higher butanol production of 4.43 g/L with a total ABE of 6.69 g/L.

Sustainable biobutanol production from pineapple waste by using Clostridium acetobutylicum B 527: Drying kinetics study.

Present investigation explores the use of pineapple peel, a food industry waste, for acetone-butanol-ethanol (ABE) production using Clostridium acetobutylicum B 527. Proximate analysis of pineapple peel shows that it contains 35% cellulose, 19% hemicellulose, and 16% lignin on dry basis. Drying experiments on pineapple peel waste were carried out in the temperature range of 60-120°C and experimental drying data was modeled using moisture diffusion control model to study its effect on ABE production. The production of ABE was further accomplished via acid hydrolysis, detoxification, and fermentation process. Maximum total sugar release obtained by using acid hydrolysis was 97g/L with 95-97% and 10-50% removal of phenolics and acetic acid, respectively during detoxification process. The maximum ABE titer obtained was 5.23g/L with 55.6% substrate consumption when samples dried at 120°C were used as a substrate (after detoxification).