scholarly journals Derived high reducing sugar and lignin colloid particles from corn stover

BMC Chemistry ◽  
2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Wei Liu ◽  
Shengnan Zhuo ◽  
Mengying Si ◽  
Mengting Yuan ◽  
Yan Shi

AbstractLignocellulosic biomass is considered as the largest potential candidate to develop alternative energy, such as biofuel, biomaterial. However, the efficient conversion of cellulose and practical utilization of lignin are great challenges for sustainable biorefinery. In this study, high reducing sugar yield and different size of lignin colloid particles (LCPs) were obtained via tetrahydrofuran–water (THF–H2O) pretreatment of corn stover (CS). THF–H2O as a co-solvent, could efficiently dissolve lignin and retain cellulose. After the pretreatment, 640.87 mg/g of reducing sugar was produced, that was 6.66-fold higher than that of the untreated CS. Meanwhile, the pretreatment liquor could form spherical LCPs with different sizes ranged from 202 to 732 nm through self-assembly. We studied the optimal pretreatment condition to simultaneously realize the high reducing sugar yield (588.4 mg/g) and excellent LCPs preparation with average size of 243 nm was under TH22 (THF–H2O pretreatment at 120 °C for 2 h). To further explore the formation of LCPs with different sizes. We studied the lignin structure changes of various conditions, concluded the size of LCPs was related to the lignin concentration and syringyl/guaiacyl (S/G) ratio. As the increase of the lignin concentration and S/G, the sizes of LCPs were increased. G-type lignin was easier to dissolve in the mild pretreatment supernatant, contributing to form smaller LCPs with a good dispersibility. In the severe condition, both of S and G-type lignin were dissolved due to the lignin depolymerization, formed the larger sphere particles. This work provides a novel perspective for the technical design of lignocellulosic biomass conversion.

2013 ◽  
Vol 724-725 ◽  
pp. 207-211 ◽  
Author(s):  
Hai Song Wang ◽  
Hong Ling Gao ◽  
Bin Li ◽  
Xin Dong Mu

For the enzymatic saccharification of lignocellulosic biomass, single acid or alkaline pretreatment is not satisfactory because of the low sugar yields together with the neutralization of residual chemicals before enzymatic hydrolysis. Herein, an acid-alkaline two-stage pretreatment process was designed to treat corn stover. During the process, the pretreated liquid from the first stage and the solid residues from the second stage were mixed together for the subsequent simultaneous enzymatic hydrolysis, where a mixture of cellulase with an activity loading of 20 FPU/g substrate, cellobiase with an activity loading of 5 U/g substrate, and xylanase with an activity loading of 200 U/g substrate was used. Compared to the single acid or alkaline pretreatment, the acid-alkaline two-stage pretreatment could significantly improve the enzymatic saccharification, and 91.2% glucose yield with 52.56% of the theoretical total reducing sugar yield was achieved after the subsequent enzymatic hydrolysis.


2019 ◽  
Author(s):  
Wei Liu ◽  
Shengnan Zhuo ◽  
Xianfa Su ◽  
Mengying Si ◽  
Kejing Zhang ◽  
...  

Abstract BackgroundLignocellulosic biomass for biofuel production was considered as an effective way to develop new energy. However, the efficient sugar conversion of cellulose and practical utilization of lignin are great challenges for sustainable biorefinery. In addition, sugar conversion and lignin utilization are generally performed separately. In this study, high reducing sugar production and multiple lignin nanoparticles preparation were realized in a pattern based on tetrahydrofuran-water (THF-H2O) pretreatment of corn straw (CS). ResultsThe maximum production of the reducing sugar was 26.79 g/l, which was significantly higher than the theoretical yield of 20.65 g/l. Lignin nanoparticles with different sizes ranged from 239 to 798 nm were prepared using dissolved lignin in the supernatant fluid from different THF-H2O pretreatment conditions through self-assembly with introducing water. The formation of lignin particles with different sizes were influenced by soluble lignin characteristics in the pretreatment liquid. The lignin molecular, functional groups, and structure were explored to elucidate the effects on the variation of lignin particles sizes by GPC, FTIR, and 2D-HSQC-NMR. The guaiacyl (G)-type lignin was easier to be dissolved in the mild pretreatment liquid, contributing to form smaller lignin nanoparticles with a good dispersibility. Comparatively, a small content of syringyl- and G-type lignin which caused by the lignin depolymerization retained in the severe pretreatment liquid to form the larger sphere particles. ConclusionsThe optimal pretreatment under TH22 (THF-H2O pretreatment at 120 °C for 2 h) simultaneously realized the utilization of all components in biomass through high reducing sugar production and the smaller lignin particles preparation. This new pattern of CS pretreatment plays a novel perspective for the technical design of lignocellulosic biomass conversion.


Author(s):  
Yohanita Restu Widihastuty ◽  
Sutini Sutini ◽  
Aida Nur Ramadhani

Pineapple leaf waste is one agricultural waste that has high cellulose content. Pineapple leaf waste's complex structure contains a bundle of packed fiber that makes it hard to remove lignin and hemicellulose structure, so challenging to produce reducing sugar. Dried pineapple leaf waste pretreated with a grinder to break its complex structure. Delignification process using 2% w/v NaOH solution at 87oC for 60 minutes has been carried out to remove lignin and hemicellulose structure so reducing sugar could be produced. Delignified pineapple leaf waste has been enzymatic hydrolyzed using cellulase enzyme (6 mL, 7 mL, and 8 mL) to produce reducing sugar. The sample was incubated in an incubator shaker at 155 rpm at 45, 55, and 60oC for 72 hours. Determination of reducing sugar yield had been carried out using the Dubois method and HPLC. The model indicated that the optimum operating condition of enzymatic hydrolysis is 7 mL of cellulase enzyme at 55oC to produce 96,673 mg/L reducing sugar. This result indicated that the enzymatic hydrolysis operating condition improved the reducing sugar yield from pineapple leaf waste. The optimum reducing sugar yield can produce biofuel by the saccharification process.


2021 ◽  
Author(s):  
Bhargava Nemmaru ◽  
Jenna Douglass ◽  
John M Yarbrough ◽  
Antonio De Chellis ◽  
Srivatsan Shankar ◽  
...  

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.


2017 ◽  
Vol 224 ◽  
pp. 405-410 ◽  
Author(s):  
Wen-Chao Li ◽  
Xia Li ◽  
Lei Qin ◽  
Jia-Qing Zhu ◽  
Xiao Han ◽  
...  

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 787 ◽  
Author(s):  
Saleem Ethaib ◽  
Rozita Omar ◽  
Mustapa Kamal Siti Mazlina ◽  
Awang Biak Dayang Radiah

This study aims to evaluate the sugar yield from enzymatic hydrolysis and the interactive effect pretreatment parameters of microwave-assisted pretreatment on glucose and xylose. Three types of microwave-assisted pretreatments of sago palm bark (SPB) were conducted for enzymatic hydrolysis, namely: microwave-sulphuric acid pretreatment (MSA), microwave-sodium hydroxide pretreatment (MSH), and microwave-sodium bicarbonate (MSB). The experimental design was done using a response surface methodology (RSM) and Box–Behenken Design (BBD). The pretreatment parameters ranged from 5–15% solid loading (SL), 5–15 min of exposure time (ET), and 80–800 W of microwave power (MP). The results indicated that the maximum total reducing sugar was 386 mg/g, obtained by MSA pretreatment. The results also illustrated that the higher glucose yield, 44.3 mg/g, was found using MSH pretreatment, while the higher xylose yield, 43.1 mg/g, resulted from MSA pretreatment. The pretreatment parameters MP, ET, and SL showed different patterns of influence on glucose and xylose yield via enzymatic hydrolysis for MSA, MSH, and MSB pretreatments. The analyses of the interactive effect of the pretreatment parameters MP, ET, and SL on the glucose yield from SPB showed that it increased with the high MP and longer ET, but this was limited by low SL values. However, the analysis of the interactive effect of the pretreatment parameters on xylose yields revealed that MP had the most influence on the xylose yield for MSA, MSH, and MSB pretreatments.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
K. Hodgson-Kratky ◽  
G. Papa ◽  
A. Rodriguez ◽  
V. Stavila ◽  
B. Simmons ◽  
...  

Abstract Background Lignocellulosic biomass is recognized as a promising renewable feedstock for the production of biofuels. However, current methods for converting biomass into fermentable sugars are considered too expensive and inefficient due to the recalcitrance of the secondary cell wall. Biomass composition can be modified to create varieties that are efficiently broken down to release cell wall sugars. This study focused on identifying the key biomass components influencing plant cell wall recalcitrance that can be targeted for selection in sugarcane, an important and abundant source of biomass. Results Biomass composition and the amount of glucan converted into glucose after saccharification were measured in leaf and culm tissues from seven sugarcane genotypes varying in fiber composition after no pretreatment and dilute acid, hydrothermal and ionic liquid pretreatments. In extractives-free sugarcane leaf and culm tissue, glucan, xylan, acid-insoluble lignin (AIL) and acid-soluble lignin (ASL) ranged from 20 to 32%, 15% to 21%, 14% to 20% and 2% to 4%, respectively. The ratio of syringyl (S) to guaiacyl (G) content in the lignin ranged from 1.5 to 2.2 in the culm and from 0.65 to 1.1 in the leaf. Hydrothermal and dilute acid pretreatments predominantly reduced xylan content, while the ionic liquid (IL) pretreatment targeted AIL reduction. The amount of glucan converted into glucose after 26 h of pre-saccharification was highest after IL pretreatment (42% in culm and 63.5% in leaf) compared to the other pretreatments. Additionally, glucan conversion in leaf tissues was approximately 1.5-fold of that in culm tissues. Percent glucan conversion varied between genotypes but there was no genotype that was superior to all others across the pretreatment groups. Path analysis revealed that S/G ratio, AIL and xylan had the strongest negative associations with percent glucan conversion, while ASL and glucan content had strong positive influences. Conclusion To improve saccharification efficiency of lignocellulosic biomass, breeders should focus on reducing S/G ratio, xylan and AIL content and increasing ASL and glucan content. This will be key for the development of sugarcane varieties for bioenergy uses.


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