Recent developments in cellulolytic enzymes for ethanol production

2022 ◽  
pp. 195-215
Author(s):  
Jitendra Kumar Saini
Author(s):  
Tuan-Dung Hoang ◽  
Nhuan Nghiem

Ethanol produced from various biobased sources (bioethanol) has been gaining high attention lately due to its potential to cut down net emissions of carbon dioxide while reducing burgeoning world dependence on fossil fuels. Global ethanol production has increased more than six-fold from 18 billion liters at the turn of the century to 110 billion liters in 2019 (1,2). Sugar cane and corn have been used as the major feedstocks for ethanol production. Lignocellulosic biomass has recently been considered as another potential feedstock. This paper reviews recent developments and current status of commercial production of ethanol across the world. The review includes the ethanol production processes used for each type of feedstock, both currently practiced at commercial scale and newly developed technologies, and production trends in various regions and countries in the world.


1969 ◽  
Vol 16 (3) ◽  
Author(s):  
Anuj K Chandel ◽  
Om V Singh ◽  
Gajula Chandrasekhar ◽  
Linga Venkateswar Rao ◽  
Mangamoori Lakshmi Narasu

The imposition of ethanol derived from biomass for blending in gasoline would make countries less dependent on current petroleum sources, which would save foreign exchange reserves, improve rural economies and provide job opportunities in a clean and safe environment. The key drivers for successful commercial ethanol production are cheap raw materials, economic pretreatment technologies, in-house cellulase production with high and efficient titers, high ethanol fermentation rates, downstream recovery of ethanol and maximum by-products utilization. Furthermore, recent developments in engineering of biomass for increased biomass, down-regulation of lignin synthesis, improved cellulase titers and re-engineering of cellulases, and process integration of the steps involved have increased the possibility of cheap bioethanol production that competes with the price of petroleum. Recently, many companies have come forward globally for bioethanol production on a large scale. It is very clear now that bioethanol will be available at the price of fossil fuels by 2010. This article intends to provide insight and perspectives on the important recent developments in bioethanol research, the commercialization status of bioethanol production, the step-wise cost incurred in the process involved, and the possible innovations that can be utilized to reduce the cost of ethanol production.


2018 ◽  
Author(s):  
Plínio R Rodrigues ◽  
Mateus FL Araújo ◽  
Tamarah L Rocha ◽  
Ronnie Von S Veloso ◽  
Lílian A Pantoja ◽  
...  

The production of lignocellulosic ethanol is one of the most promising alternatives to fossil fuels, however, this technology still faces many challenges related to the viability of the alcohol in the market. In this paper the endocarp of buriti fruit was assessed for ethanol production. The whole fruit was characterized physically and chemically and its endocarp submitted to acid and alkaline pre-treatments, which were optimized through the use of surface response methodology for removal of hemicellulose and lignin, respectively. Hemicellulose content was reduced by 88% after acid pretreatment. Alkaline pre-treatment reduced the lignin content in the recovered biomass from 11.8% to 4.2% and increased the concentration of the cellulosic fraction to 88.5%. The pre-treated biomass was saccharified by the action of cellulolytic enzymes and, in the optimized condition, was able to produce 110 g of glucose per L of hydrolyzate. Alcoholic fermentation of the enzymatic hydrolyzate bio-catalized by Saccharomyces cerevisiae resulted in a fermented medium with 4.3% ethanol and YP/S of 0.33.


Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 314
Author(s):  
Tuan-Dung Hoang ◽  
Nhuan Nghiem

Ethanol produced from various biobased sources (bioethanol) has been gaining high attention lately due to its potential to cut down net emissions of carbon dioxide while reducing burgeoning world dependence on fossil fuels. Global ethanol production has increased more than six-fold from 18 billion liters at the turn of the century to 110 billion liters in 2019, only to fall to 98.6 billion liters in 2020 due to the pandemic. Sugar cane and corn have been used as the major feedstocks for ethanol production. Lignocellulosic biomass has recently been considered as another potential feedstock due to its non-food competing status and its availability in very large quantities. This paper reviews recent developments and current status of commercial production of ethanol across the world with a focus on the technological aspects. The review includes the ethanol production processes used for each type of feedstock, both currently practiced at commercial scale and still under developments, and current production trends in various regions and countries in the world.


2015 ◽  
Vol 76 ◽  
pp. 66-71 ◽  
Author(s):  
You Ree Jung ◽  
Jang Min Park ◽  
Sun-Yeon Heo ◽  
Won-Kyung Hong ◽  
Sung-Mok Lee ◽  
...  

1983 ◽  
Vol 1 (3) ◽  
pp. 273-288 ◽  
Author(s):  
Peter L. Rogers ◽  
Mary L. Skotnicki ◽  
Kye Joon Lee ◽  
Jae Heung Lee

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1028
Author(s):  
Izumi Kumakiri ◽  
Morihisa Yokota ◽  
Ryotaro Tanaka ◽  
Yu Shimada ◽  
Worapon Kiatkittipong ◽  
...  

Ethanol is considered as a renewable transport fuels and demand is expected to grow. In this work, trends related to bio-ethanol production are described using Thailand as an example. Developments on high-temperature fermentation and membrane technologies are also explained. This study focuses on the application of membranes in ethanol recovery after fermentation. A preliminary simulation was performed to compare different process configurations to concentrate 10 wt% ethanol to 99.5 wt% using membranes. In addition to the significant energy reduction achieved by replacing azeotropic distillation with membrane dehydration, employing ethanol-selective membranes can further reduce energy demand. Silicalite membrane is a type of membrane showing one of the highest ethanol-selective permeation performances reported today. A silicalite membrane was applied to separate a bio-ethanol solution produced via high-temperature fermentation followed by a single distillation. The influence of contaminants in the bio-ethanol on the membrane properties and required further developments are also discussed.


2018 ◽  
Author(s):  
Plínio R Rodrigues ◽  
Mateus FL Araújo ◽  
Tamarah L Rocha ◽  
Ronnie Von S Veloso ◽  
Lílian A Pantoja ◽  
...  

The production of lignocellulosic ethanol is one of the most promising alternatives to fossil fuels, however, this technology still faces many challenges related to the viability of the alcohol in the market. In this paper the endocarp of buriti fruit was assessed for ethanol production. The whole fruit was characterized physically and chemically and its endocarp submitted to acid and alkaline pre-treatments, which were optimized through the use of surface response methodology for removal of hemicellulose and lignin, respectively. Hemicellulose content was reduced by 88% after acid pretreatment. Alkaline pre-treatment reduced the lignin content in the recovered biomass from 11.8% to 4.2% and increased the concentration of the cellulosic fraction to 88.5%. The pre-treated biomass was saccharified by the action of cellulolytic enzymes and, in the optimized condition, was able to produce 110 g of glucose per L of hydrolyzate. Alcoholic fermentation of the enzymatic hydrolyzate bio-catalized by Saccharomyces cerevisiae resulted in a fermented medium with 4.3% ethanol and YP/S of 0.33.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5275
Author(s):  
Plínio R. Rodrigues ◽  
Mateus F.L. Araújo ◽  
Tamarah L. Rocha ◽  
Ronnie Von S. Veloso ◽  
Lílian A. Pantoja ◽  
...  

The production of lignocellulosic ethanol is one of the most promising alternatives to fossil fuels; however, this technology still faces many challenges related to the viability of the lignocellulosic alcohol in the market. In this paper the endocarp of buriti fruit was assessed for ethanol production. The fruit endocarp was characterized physically and chemically. Acid and alkaline pre-treatments were optimized by surface response methodology for removal of hemicellulose and lignin from the biomass. Hemicellulose content was reduced by 88% after acid pretreatment. Alkaline pre-treatment reduced the lignin content in the recovered biomass from 11.8% to 4.2% and increased the concentration of the cellulosic fraction to 88.5%. The pre-treated biomass was saccharified by the action of cellulolytic enzymes and, under optimized conditions, was able to produce 110 g of glucose per L of hydrolyzate. Alcoholic fermentation of the enzymatic hydrolyzate performed by Saccharomyces cerevisiae resulted in a fermented medium with 4.3% ethanol and a yield of product per substrate (YP/S) of 0.33.


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