Influence of Enzymatic Cocktails on Conversion of Agricultural Lignocellulose to Fermentable Sugars

2017 ◽  
Vol 68 (2) ◽  
pp. 373-377
Author(s):  
Teodor Vintila ◽  
Vasile Daniel Gherman ◽  
Nicolae Popa ◽  
Dumitru Popescu ◽  
Carmen Buzatu ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Culture Media ◽  
Fermentable Sugars ◽  
Cellulolytic Enzymes ◽  
Crystalline Cellulose ◽  
Agricultural Biomass ◽  
Residual Biomass ◽  
Hydrolysis Process ◽  
High Yields ◽  
Hydrolysis Of

Agricultural lignocellulosic biomass is regarded as an important source of biofuels, especially bioethanol and biohydrogen. The following aspects have been studied: the effect of type of substrate used in production of cellulolytic enzymes, the activity of several enzymatic cocktails used to hydrolyse three types of agricultural biomass and the influence of provenience of enzymatic cocktails on sugars yields in the hydrolysis process. Fungi investigated in this study (T. longibrachiatum DSM 769) release higher titter of enzymes when raw, unpretreated agriculture residual biomass is used as substrate and inducer for biosynthesis of cellulolytic enzymes. Cellulolytic enzymes produced in culture media containing a certain type of agricultural lignocellulosic biomass as substrate, can be used in hydrolysis of other types of agricultural lignocellulosic biomass with similar sugar yields. Cellulases produced in culture media containing purified crystalline cellulose as substrate does not contain all necessary types of enzymes to hydrolyze lignocellulosic complex from agricultural biomass to produce high yields of sugars. On-site production of cellulases can be an effective approach biorefinery of lignocellulose to produce biofuels or other biochemicals by fermentation.

scholarly journals Supercharged Cellulases Show Reduced Non-Productive Binding, But Enhanced Activity, on Pretreated Lignocellulosic Biomass

2021 ◽  
Author(s):  
Bhargava Nemmaru ◽  
Jenna Douglass ◽  
John M Yarbrough ◽  
Antonio De Chellis ◽  
Srivatsan Shankar ◽  
...  
Keyword(s):  
Cell Wall ◽  
Corn Stover ◽  
Lignocellulosic Biomass ◽  
Hydrolytic Activity ◽  
Fine Tuning ◽  
Cellulolytic Enzymes ◽  
Crystalline Cellulose ◽  
Cell Wall Components ◽  
Carbohydrate Binding Modules ◽  
Wall Components

Non-productive adsorption of cellulolytic enzymes to various plant cell wall components, such as lignin and cellulose, necessitates high enzyme loadings to achieve efficient conversion of pretreated lignocellulosic biomass to fermentable sugars. Carbohydrate-binding modules (CBMs), appended to various catalytic domains (CDs), promote lignocellulose deconstruction by increasing targeted substrate-bound CD concentration but often at the cost of increased non-productive enzyme binding. Here, we demonstrate how a computational protein design strategy can be applied to a model endocellulase enzyme (Cel5A) from Thermobifida fusca to allow fine-tuning its CBM surface charge, which led to increased hydrolytic activity towards pretreated lignocellulosic biomass (e.g., corn stover) by up to ~330% versus the wild-type Cel5A control. We established that the mechanistic basis for this improvement arises from reduced non-productive binding of supercharged Cel5A mutants to cell wall components such as crystalline cellulose (up to 1.7-fold) and lignin (up to 1.8-fold). Interestingly, supercharged Cel5A mutants that showed improved activity on various forms of pretreated corn stover showed increased reversible binding to lignin (up to 2.2-fold) while showing no change in overall thermal stability remarkably. In general, negative supercharging led to increase hydrolytic activity towards both pretreated lignocellulosic biomass and crystalline cellulose whereas positive supercharging led to a reduction of hydrolytic activity. Overall, selective supercharging of protein surfaces was shown to be an effective strategy for improving hydrolytic performance of cellulolytic enzymes for saccharification of real-world pretreated lignocellulosic biomass substrates. Future work should address the implications of supercharging cellulases from various families on inter-enzyme interactions and synergism.

scholarly journals Eco-friendly consolidated process for co-production of xylooligosaccharides and fermentable sugars using self-providing xylonic acid as key pretreatment catalyst

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xin Zhou ◽  
Yong Xu
Keyword(s):  
Value Added ◽  
Glucose Production ◽  
Gluconobacter Oxydans ◽  
Fermentable Sugars ◽  
Acid Pretreatment ◽  
Cellulose Conversion ◽  
Xylonic Acid ◽  
Balance Analysis ◽  
High Yields ◽  
Hydrolysis Of

Abstract Background Obtaining high-value products from lignocellulosic biomass is central for the realization of industrial biorefinery. Acid pretreatment has been reported to yield xylooligosaccharides (XOS) and improve enzymatic hydrolysis. Moreover, xylose, an inevitable byproduct, can be upgraded to xylonic acid (XA). The aim of this study was to valorize sugarcane bagasse (SB) by starting with XA pretreatment for XOS and glucose production within a multi-product biorefinery framework. Results SB was primarily subjected to XA pretreatment to maximize the XOS yield by the response surface method (RSM). A maximum XOS yield of 44.5% was achieved by acid pretreatment using 0.64 M XA for 42 min at 154 °C. Furthermore, XA pretreatment can efficiently improve enzymatic digestibility, and achieved a 90.8% cellulose conversion. In addition, xylose, the inevitable byproduct of the acid-hydrolysis of xylan, can be completely converted to XA via bio-oxidation of Gluconobacter oxydans (G. oxydans). Subsequently, XA and XOS can be simultaneously separated by electrodialysis. Conclusions XA pretreatment was explored and exhibited a promising ability to depolymerize xylan into XOS. Mass balance analysis showed that the maximum XOS and fermentable sugars yields reached 10.5 g and 30.9 g per 100 g raw SB, respectively. In summary, by concurrently producing XOS and fermentable sugars with high yields, SB was thus valorized as a promising feedstock of lignocellulosic biorefinery for value-added products.

Use of ionic liquids for improvement of cellulosic ethanol production

BioResources ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 1-2
Author(s):  
Qijun Wang ◽  
Yuanxin Wu ◽  
Shengdong Zhu
Keyword(s):  
Ionic Liquids ◽  
Enzymatic Hydrolysis ◽  
Ethanol Production ◽  
Lignocellulosic Biomass ◽  
Cellulosic Ethanol ◽  
Heterogeneous Reaction ◽  
Reaction System ◽  
The Other ◽  
Fermentable Sugars ◽  
Hydrolysis Process

Cellulosic ethanol production has drawn much attention in recent years. However, there remain significant technical challenges before such production can be considered as economically feasible at an industrial scale. Among them, the efficient conversion of carbohydrates in lignocellulosic biomass into fermentable sugars is one of the most challenging technical difficulties in cellulosic ethanol production. Use of ionic liquids has opened new avenues to solve this problem by two different pathways. One is pretreatment of lignocellulosic biomass using ionic liquids to increase its enzymatic hydrolysis efficiency. The other is to transform the hydrolysis process of lignocellulosic biomass from a heterogeneous reaction system to a homogeneous one by dissolving it into ionic liquids, thus improving its hydrolysis efficiency.

Hydrolysis of Lignocellulosics into Fermentable Sugars for Cellulosic Ethanol Production: An Overview

2012 ◽  
Vol 538-541 ◽  
pp. 2401-2404
Author(s):  
Jun Ping Zhuang ◽  
Xue Ping Li ◽  
Ying Liu
Keyword(s):  
Cellulosic Ethanol ◽  
Hot Water ◽  
Fermentable Sugars ◽  
Future Research ◽  
Water Pretreatment ◽  
Hydrolysis Of Cellulose ◽  
Great Pressure ◽  
High Yields ◽  
Hot Water Pretreatment ◽  
Hydrolysis Of

Facing great pressure of economic growth and energy crisis, China has paid more attention to the renewable energy and cellulosic ethanol has received increasing attention in recent years. The key from lignocelluloses to bioethanol is how to produce fermentable sugars effectively by hydrolysis of cellulose. Chemical, biological pretreatment and hot water pretreatment are considered as three important techniques for high yields of fermentable sugars from lignocellulosics. In this review, the three important techniques for high yields of fermentable sugars from lignocellulosics and the pretreatment study status, challenges, and future research targets were discussed.

scholarly journals Biological Pretreatment of Corn Stover for Enhancing Enzymatic Hydrolysis Using Thermoalkalotolerant Cellulolytic Enzymes Produced by Bacillus sp. P3

2021 ◽  
Author(s):  
Yanwen Wu ◽  
Haipeng Guo ◽  
Md. Shafiqur Rahman ◽  
Xuantong Chen ◽  
Jinchi Zhang ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Corn Stover ◽  
Fermentation Broth ◽  
Removal Rate ◽  
Enzymatic Saccharification ◽  
Cellulolytic Enzymes ◽  
Biological Pretreatment ◽  
Hydrolysis Process ◽  
Hemicellulose Removal ◽  
Hydrolysis Of

Abstract The biological pretreatment for the enzymatic hydrolysis of lignocellulosic biomasses largely depends on an effective pretreatment process. A significant enhancement of enzymatic saccharification was obtained with corn stover using Bacillus sp. P3. The hemicellulose removal from corn stover by the strain Bacillus sp. P3 was evaluated for enhancing subsequent enzymatic hydrolysis. Therefore, our study revealed that an alkaline resistant xylanase produced by Bacillus sp. P3 in fermentation broth led to a substantially enhanced hemicellulose removal rate from corn stover within pH 9.36–9.68. However, after 20 d pretreatment of corn stover by the strain P3, the glucan content was increased by 51% and the xylan content was decreased by 35%. After 72 h of saccharification using 20 U g− 1 of commercial cellulase, the yield of reducing sugar released from 20 d pretreated corn stover was increased by 56% in comparison to the untreated corn stover. Therefore, the use of the strain P3 could be a promising approach to pretreat corn stover for enhancing the enzymatic hydrolysis process of industrial bioenergy productions.

scholarly journals Residual biomass from food processing industry in Cameroon as feedstock for second-generation biofuels

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 3731-3745
Author(s):  
Teodor Vintila ◽  
Ioana Ionel ◽  
Tagne Tiegam Rufis Fregue ◽  
Adriana Raluca Wächter ◽  
Calin Julean ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Second Generation ◽  
Electricity Consumption ◽  
Electricity Production ◽  
Cellulolytic Enzymes ◽  
Oil Consumption ◽  
Energy Potential ◽  
Residual Biomass ◽  
Cellulosic Sugars ◽  
Hydrolysis Of

The yields in bioconversion of residues produced in the Cameroon food industry to liquid and gaseous biofuels were evaluated and the potential of these residues as feedstock for renewable energy production in Cameroon were assessed. Residues generated after processing avocado, cocoa, and peanut crops were converted at laboratory-scale to second-generation gaseous biofuels (biogas) and liquid biofuels (ethanol). Mechanical (milling), thermal-chemical (steam-NaOH), and microwave pretreatments were applied before hydrolysis of biomass using cellulolytic enzymes. Cellulosic sugars production potential was also assessed. The energy conversion rate was higher when anaerobic digestion technology was applied to convert the tested biomass to methane. The total Cameroon potential under anaerobic digestion technology is over 330,000 m3, which represents 28% from oil consumption or 5.39% from electricity consumption when lignocellulosic ethanol technology was applied. The national potential was assessed up to 200,000 kg, representing 17% from oil consumption in transport or 3.19% from electricity consumption. Overall, the share of energy potential of the tested residual biomass is important when compared to fossil fuel consumption in Cameroon and represents an important potential feedstock for electricity production.

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