Countercurrent enzymatic saccharification of pretreated corn stover part 2: Lime + shock pretreated corn stover and commercial approach

Liang, Chao; Lonkar, Sagar; Darvekar, Pratik; Bond, Austin; Zentay, Agustin N.; Holtzapple, Mark T.; Karim, M. Nazmul

doi:10.1016/j.biombioe.2016.12.003

Cited by 5 publications

(12 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Antibiotic solutions (0.4 mL tetracycline solution and 0.3 mL cycloheximide solution) were introduced to every stage and the desired amount of enzymes was added to a specific location (Train 1: 2 mg/g to Stage 4; Train 2: 5 mg/g to Stage 5). When the sugar concentrations from each stage did not show significant change over a relatively long time (e.g., 15 days), the system was determined to reach steady state [8–10, 18]. Table 1 summarizes the operating parameters of the two trains.…”

Section: Methodsmentioning

confidence: 99%

“…As substrate is hydrolyzed, traditional batch enzymatic saccharification cannot fully use substrate because biomass becomes less reactive [4, 5], while the enzymes become increasingly inhibited by accumulated product; therefore, high enzyme loadings are usually required to reach high conversions [6, 7]. To overcome these obstacles, countercurrent enzymatic saccharification was developed, where the least reactive biomass contacts the lowest glucose concentration and the product is removed continuously from the system, thus reducing product inhibition [8–10]. This approach more fully utilizes enzymes and therefore reduces the enzyme loadings and lowers the cost of sugar and biofuel production.…”

Section: Introductionmentioning

confidence: 99%

“…The great reduction resulted from the inherent benefits of countercurrent saccharification as well as a longer residence time. Lonkar et al [9] and Liang et al [10] continued this study with pretreated biomass. To achieve the same glucan conversion, as compared to batch, countercurrent saccharification reduced enzyme loadings up to 1.6 and 1.9 times with lime-pretreated and lime + shock-treated corn stover, respectively.

Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Liang et al [10] showed that adding a volatile antimicrobial prevented contamination even when purposely assaulted with an active culture of soil-derived microorganisms; thus, extremely long residence times can be employed. The volatile antimicrobial can be removed from the product sugars and hence is recycled.…”

Section: Introductionmentioning

confidence: 99%

“…The volatile antimicrobial can be removed from the product sugars and hence is recycled. According to Liang et al [10], this technology can produce sugars for about $0.26 to $0.35/kg including the cost of feedstock, pretreatment, and enzyme. As a reference point, the average price of sugar has been about $0.40/kg during the past 10 years [11].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Kinetic modeling of countercurrent saccharification

Liang

Karim

et al. 2019

Biotechnol Biofuels

Self Cite

View full text Add to dashboard Cite

Background Countercurrent saccharification is a promising way to minimize enzyme loading while obtaining high conversions and product concentrations. However, in countercurrent saccharification experiments, 3–4 months are usually required to acquire a single steady-state data point. To save labor and time, simulation of this process is necessary to test various reaction conditions and determine the optimal operating point. Previously, a suitable kinetic model for countercurrent saccharification has never been reported. The Continuum Particle Distribution Modeling (CPDM) satisfactorily predicts countercurrent fermentation using mixed microbial cultures that digest various feedstocks. Here, CPDM is applied to countercurrent enzymatic saccharification of lignocellulose. Results CPDM was used to simulate multi-stage countercurrent saccharifications of a lignocellulose model compound (α-cellulose). The modified HCH-1 model, which accurately predicts long-term batch saccharification, was used as the governing equation in the CPDM model. When validated against experimental countercurrent saccharification data, it predicts experimental glucose concentrations and conversions with the average errors of 3.5% and 4.7%, respectively. CPDM predicts conversion and product concentration with varying enzyme-addition location, total stage number, enzyme loading, liquid residence time (LRT), and solids loading rate (SLR). In addition, countercurrent saccharification was compared to batch saccharification at the same conversion, product concentration, and reactor volume. Results show that countercurrent saccharification is particularly beneficial when the product concentration is low. Conclusions The CPDM model was used to simulate multi-stage countercurrent saccharification of α-cellulose. The model predictions agreed well with the experimental glucose concentrations and conversions. CPDM prediction results showed that the enzyme-addition location, enzyme loading, LRT, and SLR significantly affected the glucose concentration and conversion. Compared to batch saccharification at the same conversion, product concentration, and reactor volume, countercurrent saccharification is particularly beneficial when the product concentration is low.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fig.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Kinetic modeling of countercurrent saccharification

Liang

Karim

et al. 2019

Biotechnol Biofuels

Self Cite

View full text Add to dashboard Cite

show abstract

Assessment of shock pretreatment and alkali pretreatment on corn stover using enzymatic hydrolysis

Olokede

Hsu

Schiele

et al. 2021

Biotechnology Progress

View full text Add to dashboard Cite

This study investigates digestibility enhancements of lignocellulose from shock pretreatment, alkaline pretreatment, and combination. Shock pretreatment subjects aqueous slurries of lignocellulose to shock waves, which disrupts its structure rendering it more susceptible to hydrolysis. Alkaline pretreatment submerges the biomass in aqueous alkali (NaOH, Ca(OH) 2 ), which removes lignin and acetyl groups. As indicators of digestibility, cellulase (CTec3) and hemicellulase (HTec3) were used to saccharify the pretreated corn stover and the resulting filtrate which contains about 10% of the sugars. Shock is most effective when it precedes alkaline pretreatment, presumably because it opens the biomass structure and enhances diffusion of pretreatment chemicals. Lignocellulose digestibility from calcium hydroxide treatment improves significantly with oxygen addition. In contrast, sodium hydroxide is a more potent alkali, and thereby eliminates the need for oxygen to enhance pretreatment.At low hydroxide loadings (<4 g OH À /100 g dry biomass), both NaOH and Ca(OH) 2 provide similar increases in digestibility; however, at high hydroxide loadings, NaOH is superior. For animal feed, Ca(OH) 2 treatment is recommended, because residual calcium ions are valuable nutrients. In contrast, for methane-arrested anaerobic digestion, NaOH treatment is preferred because NaHCO 3 is a stronger buffer. At 50 C, shock pretreatment improves sugar yields at all NaOH loadings. The effect of shock is most pronounced when the no-shock control employed the same soakingand-drying procedure as the shock treatment. The recommended conditions are shock treatment (5.52 bar [abs] initial H 2 /O 2 pressure) followed by 50 C alkaline treatment with NaOH loading of 4 g OH À /100 g dry biomass for 1 h.

show abstract

Process intensification strategies for enhanced holocellulose solubilization: Beneficiation of pineapple peel waste for cleaner butanol production

Khedkar

Nimbalkar

Kamble

et al. 2018

Journal of Cleaner Production

View full text Add to dashboard Cite

Biorefinery sector has become a serious dispute for cleaner and sustainable development in recent years. In the present study, pretreatment of pineapple peel waste was carried out in high pressure reactor using various pretreatment-enhancers. The type and concentration effect of each enhancer on hemicellulose solubilization was systematically investigated. The binary acid (phenol + sulfuric acid) at 180 °C was found to be superior amongst other studied enhancers, giving 81.17% (w/v) hemicellulose solubilization in liquid-fraction under optimized conditions. Solid residue thus obtained was subjected to enzymatic hydrolysis that resulted into 24.50% (w/v) cellulose breakdown. Treated solid residue was further characterized by scanning electron microscopy and Fourier transform infrared spectroscopy to elucidate structural changes. The pooled fractions (acid treated and enzymatically hydrolyzed) were fermented using Clostridium acetobutylicum NRRL B 527 which resulted in butanol production of 5.18 g/L with yield of 0.13 g butanol/g sugar consumed. Therefore, pretreatment of pineapple peel waste evaluated in this study can be considered as milestone in utilization of low cost feedstock, for bioenergy production.

show abstract

Countercurrent enzymatic saccharification of pretreated corn stover part 2: Lime + shock pretreated corn stover and commercial approach

Cited by 5 publications

References 11 publications

Kinetic modeling of countercurrent saccharification

Kinetic modeling of countercurrent saccharification

Assessment of shock pretreatment and alkali pretreatment on corn stover using enzymatic hydrolysis

Process intensification strategies for enhanced holocellulose solubilization: Beneficiation of pineapple peel waste for cleaner butanol production

Contact Info

Product

Resources

About