scholarly journals NaOH-Catalyzed Fractionation of Rice Husk Followed by Concomitant Production of Bioethanol and Furfural for Improving Profitability in Biorefinery

2021 ◽  
Vol 11 (16) ◽  
pp. 7508
Author(s):  
Hyun Jin Jung ◽  
Kyeong Keun Oh
Keyword(s):  
Rice Husk ◽  
Removal Rate ◽  
Enzymatic Saccharification ◽  
High Yield ◽  
Optimal Conditions ◽  
Essential Factor ◽  
Fed Batch ◽  
Fed Batch Fermentation ◽  
High Ethanol ◽  
Furfural Production

The alkaline fractionation of rice husk (RH) with NaOH was optimized for the purpose of obtaining a high-yield recovery of glucan and increasing the removal rate for lignin and ash, resulting in a hemicellulose-rich hydrolysate. The determined optimal conditions were a temperature of 150 °C, reaction time of 45 min, and NaOH concentration of 6% (w/v). The glucan content in the fractionated RH (Fr. RH) was 80.1%, which was significantly increased compared to the raw RH (35.6%). High glucan content in the fractionated solid residue is the most essential factor for minimizing enzyme dosages in enzymatic saccharification. The final enzymatic digestibilities (at 96 h) of raw and NaOH-Fr. RH with cellulase loadings of 30 FPU/g cellulose were 10.5% and 81.3%, respectively. Approximately 71.6% of the xmg content (mainly xylose) was concomitantly degraded into the fractionated hydrolysate (Fr. Hydrolysate). When this hydrolysate was acidified with sulfuric acid and subjected to heat treatment, a furfural production yield of about 64.9% was obtained. The results show that two-stage fed-batch fermentation with glucan-rich Fr. RH has the potential to achieve high-ethanol titers of 28.7 g/L.

Study on the Removal Effect of Chromium(VI) in Wastewater by Rice Husk

2014 ◽  
Vol 1073-1076 ◽  
pp. 825-828 ◽  
Author(s):  
Xue Min Dai ◽  
Shu Na Wang ◽  
Xia Wang
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Ph Value ◽  
Removal Rate ◽  
Experimental Studies ◽  
Optimal Conditions ◽  
Solution Ph ◽  
Adsorption Time ◽  
Chromium Vi

Rice husk was used as an adsorbent to study the adsorption of Cr (VI) from wastewater, Based on the experimental studies on influences of the particle size of rice husk, solution pH value, adsorption time, temperature and rice husk dose, the optimal conditions of the adsorption were determined as follows: temperature of 35°C, pH of 2, the particle size of rice husk in the range of 80-100 mesh, adsorption time of 3h, dose of 30g/0.2g. Under the optimal conditions, the removal rate of chromium from wastewater by rice husk can reach 91%.

scholarly journals Production of L (+) Lactic Acid by Lactobacillus casei Ke11: Fed Batch Fermentation Strategies

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 151
Author(s):  
Paola Monteiro de Oliveira ◽  
Larissa Provasi Santos ◽  
Luciana Fontes Coelho ◽  
Paulo Marcelo Avila Neto ◽  
Daiane Cristina Sass ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Batch Fermentation ◽  
Lactobacillus Casei ◽  
Culture Media ◽  
Feeding Strategy ◽  
High Yield ◽  
Feeding Strategies ◽  
Efficient Production ◽  
Fed Batch ◽  
Fed Batch Fermentation

Lactic acid and its derivatives are widely used in pharmaceutical, leather, textile and food industries. However, until now there have been few systematic reports on fed-batch fermentation for efficient production and high concentration of l-lactic acid by lactic acid bacteria. This study describes the obtainment of L (+) lactic acid from sucrose using the Lactobacillus casei Ke11 strain through different feeding strategies using an accessible pH neutralizer such as CaCO3. The exponential feeding strategy can increase lactic acid production and productivity (175.84 g/L and 3.74 g/L/h, respectively) with a 95% yield, avoiding inhibition by high initial substrate concentration and, combined with the selected agent controller, avoids the cellular stress that could be caused by the high osmotic pressure of the culture media. The purification of the acid using charcoal and celite, followed by the use of a cation exchange column proved to be highly efficient, allowing a high yield of lactic acid, high removal of sugars and proteins. The described process shows great potential for the production of lactic acid, as well as the simple, efficient and low-cost purification method. This way, this work is useful to the large-scale fermentation of L. casei Ke11 for production of l-lactic acid.

scholarly journals Redirection of the central metabolism of Klebsiella pneumoniae towards dihydroxyacetone production

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Shaoqi Sun ◽  
Yike Wang ◽  
Lin Shu ◽  
Xiyang Lu ◽  
Qinghui Wang ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Triosephosphate Isomerase ◽  
Product Formation ◽  
Dihydroxyacetone Phosphate ◽  
Optimal Conditions ◽  
Glycerol Production ◽  
Fed Batch ◽  
Total Conversion ◽  
Fed Batch Fermentation ◽  
Catabolism Pathway

Abstract Background Klebsiella pneumoniae is a bacterium that can be used as producer for numerous chemicals. Glycerol can be catabolised by K. pneumoniae and dihydroxyacetone is an intermediate of this catabolism pathway. Here dihydroxyacetone and glycerol were produced from glucose by this bacterium based a redirected glycerol catabolism pathway. Results tpiA, encoding triosephosphate isomerase, was knocked out to block the further catabolism of dihydroxyacetone phosphate in the glycolysis. After overexpression of a Corynebacterium glutamicum dihydroxyacetone phosphate dephosphorylase (hdpA), the engineered strain produced remarkable levels of dihydroxyacetone (7.0 g/L) and glycerol (2.5 g/L) from glucose. Further increase in product formation were obtained by knocking out gapA encoding an iosenzyme of glyceraldehyde 3-phosphate dehydrogenase. There are two dihydroxyacetone kinases in K. pneumoniae. They were both disrupted to prevent an inefficient reaction cycle between dihydroxyacetone phosphate and dihydroxyacetone, and the resulting strains had a distinct improvement in dihydroxyacetone and glycerol production. pH 6.0 and low air supplement were identified as the optimal conditions for dihydroxyacetone and glycerol production by K, pneumoniae ΔtpiA-ΔDHAK-hdpA. In fed batch fermentation 23.9 g/L of dihydroxyacetone and 10.8 g/L of glycerol were produced after 91 h of cultivation, with the total conversion ratio of 0.97 mol/mol glucose. Conclusions This study provides a novel and highly efficient way of dihydroxyacetone and glycerol production from glucose.

Sign in / Sign up

Export Citation Format

Share Document