scholarly journals Two-stage alkaline and acid pretreatment applied to sugarcane bagasse to enrich the cellulosic fraction and improve enzymatic digestibility

Detritus ◽  
2020 ◽  
pp. 106-113
Author(s):  
Longinus Ifeanyi Igbojionu ◽  
Cecilia Laluce ◽  
Edison Pecoraro
Keyword(s):  
Sugarcane Bagasse ◽  
Maleic Acid ◽  
Ethanol Yield ◽  
High Yield ◽  
Enzymatic Digestibility ◽  
Acid Pretreatment ◽  
Two Stage ◽  
Second Stage ◽  
One Stage ◽  
Naoh Pretreatment

Sugarcane bagasse (SB) is made up of cellulose (32-43%), hemicellulose (19-34%) and lignin (14-30%). Due to high recalcitrant nature of SB, pretreatment is required to deconstruct its structure and enrich the cellulosic fraction. A two-stage NaOH and maleic acid pretreatment was applied to SB to enrich its cellulosic fraction. SB used in the present study is composed of cellulose (40.4 wt%), hemicellulose (20.9 wt%), lignin (22.5 wt%) and ash (4.0 wt%). After one-stage NaOH pretreatment, its cellulosic fraction increased to 61.8 wt% and later increased to 80.1 wt% after the second-stage acid pretreatment. Lignin fraction decreased to 3.0 wt% after one-stage NaOH pretreatment and remained unaffected after the acid pretreatment step. Hemicellulose fraction decreased substantially after the second-stage pretreatment with maleic acid. Pretreated SB displayed high crystallinity index and improved enzymatic digestibility. Hydrolysates of pretreated SB contained very low amount of xylose and subsequent fermentation by Saccharomyces cerevisiae -IQAr/45-1 resulted to ethanol level of 8.94 g/L. Maximal ethanol yield of 0.49 g/g (95.8% of theoretical yield) and productivity of 0.28 g/L/h was attained. At the same time, biomass yield and productivity of 0.47 g/g and 0.27 g/L/h respectively were obtained. Two-stage NaOH and maleic acid pretreatment led to ~ two-fold increase in cellulosic fraction and enhanced the enzymatic digestibility of SB up to 70.4%. The resulted enzymatic hydrolysate was efficiently utilized by S. cerevisiae -IQAr/45-1 to produce high yield of ethanol. Thus, optimization of enzymatic hydrolysis at low enzyme loading is expected to further improve the process and reduce cost.

scholarly journals Use of biogas biscuit meal EKPO-EB for agricultural biogas plant for substitution of energy crops utilization with organic waste

2015 ◽  
Vol 17 (3) ◽  
pp. 40-46
Author(s):  
Kateřina Chamrádová ◽  
Jiří Rusín
Keyword(s):  
Anaerobic Digestion ◽  
Laboratory Experiment ◽  
Methane Production ◽  
Organic Waste ◽  
Dry Mass ◽  
Corn Silage ◽  
Biogas Plant ◽  
High Yield ◽  
Two Stage ◽  
Second Stage

Abstract A laboratory experiment of two-stage mesophilic, low-dry mass, anaerobic digestion was carried out, focused on verifying the benefit of processing the biscuit meal EKPO-EB instead of triticale silage Agostino (GPS) and corn silage LG3266 in a regular batch for the agricultural biogas station in Pustějov. While anaerobic digestion of ensilages is largely difficult due to the content of lignocellulose, biscuit meal provides a high yield of biogas or methane, respectively, thanks to its high content of simple saccharides and lipids. When the original GPS (or the replacement EKPO-EB, respectively) represented 0.81% of weight of the daily input mixture dose for the first stage, the rise in volumetric methane production was 20% which is significant. The biscuit meal EKPO-EB decomposes almost completely in the first stage. Later, when the EKPO-EB represented 1.63% of weight of the daily input mixture dose for the first stage, the rise in volumetric methane production was 54% in the first stage and 16% in the second stage.

Dysplasia epiphysealis hemimelica affecting the subtalar joint

1994 ◽  
Vol 84 (11) ◽  
pp. 580-582 ◽  
Author(s):  
S Graviet ◽  
JL Thomas
Keyword(s):  
Subtalar Joint ◽  
Transverse Plane ◽  
Two Stage ◽  
Bone Deformity ◽  
Second Stage ◽  
One Stage ◽  
Dysplasia Epiphysealis Hemimelica

The case presented here is unique because of the location of the lesions and the extent to which the foot was affected. A two-stage procedure was performed because of the degree of bone deformity. The first stage of the procedure was directed at reducing osseous proliferation; the second stage addressed the frontal and transverse plane deformities. One-stage procedures can be used in treating less severe deformities.

scholarly journals PRODUKSI BIOHIDROGEN DARI HIDROLISAT AMPAS TAHU SECARA FERMENTASI ANAEROB MENGGUNAKAN KULTUR CAMPURAN

REAKTOR ◽  
2014 ◽  
Vol 15 (2) ◽  
pp. 87
Author(s):  
Amir Husin ◽  
Sarto Sarto ◽  
Siti Syamsiah ◽  
Imam Prasetyo
Keyword(s):  
Solid Waste ◽  
Reducing Sugar ◽  
Hydrogen Yield ◽  
Batch Experiments ◽  
Two Stage ◽  
Second Stage ◽  
One Stage ◽  
Initial Ph ◽  
Two Stages ◽  
By Products

Ampas tahu merupakan produk samping industri pengolahan tahu berbahan dasar kacang kedelai (Glysine max.).  Dalam studi ini, ampas tahu yang telah mengalami perlakuan-awal dengan metode yang berbeda dikonversi menjadi hidrogen menggunakan kultur campuran.  Pengaruh perlakuan-awal asam satu-tahap (0,5% dan 10% berat HCl) dan dua-tahap (tahap I 0,5%  dan tahap II 10% berat HCl) terhadap sakarifikasi ampas tahu juga diinvestigasi.  Lebih lanjut, pengaruh perlakuan awal asam satu-tahap maupun dua-tahap terhadap produksi hidrogen dan efisiensi degradasi gula tereduksi dibandingkan.  Yield total gula-tereduksi 503,73 mg/g ampas tahu diperoleh dari perlakuan-awal asam dua-tahap.  Nilai ini kurang lebih 4 kali lebih tinggi dibanding hasil dari perlakuan-awal asam satu-tahap menggunakan 0,5% berat HCl. Studi produksi biohidrogen dilakukan secara batch menggunakan kultur campuran dengan kondisi reaksi  35oC dan pH awal 6,5,  Hasil percobaan menunjukkan, bahwa yield hidrogen kumulatif  maksimum 0,928  mmol/g  ampas tahu diperoleh dari perlakuan  asam dua-tahap  atau meningkat 1,8 kali dibanding perlakuan satu-tahap menggunakan 0,5% berat HCl. Key words : ampas tahu,  perlakuan asam, produksi hidrogen Abstract Tofu solid waste is one of the by-products of tofu-processing industry.  In this study, batch experiments were carried out to convert tofu solid waste pretreated by different methods into hydrogen using mixed culture.  The effects of one-stage (0.5% or 10% HCl) and two-stage (first stage 0.5% HCl) and second stage 10% HCl) pretreatments on the saccharification of tofu solid waste were also studied.  Furthermore, the effects of  and/or  two- stages acid pretreatments on hydrogen production and degradation efficiencies the reducing-sugar (RS) were compared.  A maximum total RS yield of 503.73 mg/g-tofu solid waste was obtained from substrate pretreated with two-stages method.  It was approximately 4-fold greater than that from substrate pretreated with one-stage method using 0.5% wt HCl. At the reaction condition of 35oC, initial pH =  6.5, and RS concentration based on 2 grams of tofu solid waste pretreated, a maximum cumulative hydrogen yield was 0.928  mmol/g-tofu solid waste from substrate  pretreated  with  two-stages method.  It was approximately 1.8-fold greater than that from substrate pretreated with one-stage method using 0.5% wt HCl. The results show that two-stage acid preteatment can enhancing the amount of  reducing sugar in the mixture and hydrogen yield from tofu solid wastes. 

scholarly journals Two-Stage Aeration Fermentation Strategy to Improve Bioethanol Production by Scheffersomyces stipitis

Fermentation ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. 97 ◽  
Author(s):  
Tiago Henriques ◽  
Susana Pereira ◽  
Luísa Serafim ◽  
Ana Xavier
Keyword(s):  
Ethanol Production ◽  
Ethanol Yield ◽  
Process Conditions ◽  
Agitation Rate ◽  
Bioethanol Production ◽  
Scheffersomyces Stipitis ◽  
Two Stage ◽  
Dissolved Oxygen Tension ◽  
Second Stage ◽  
Main Challenge

Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high concentration of pentose sugars, besides some hexoses suitable for bioethanol production by Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in specific microaerophilic conditions required by S. stipitis is the main challenge for ethanol production. The present study aimed to improve the ethanol production from HSSL by S. stipitis through a two-stage aeration fermentation. Experiments with controlled dissolved oxygen tension (DOT) in the first stage and oxygen restriction in the second stage were carried out. The best results were obtained with DOT control at 50% in the first stage, where the increase of oxygen availability provided faster growth and higher biomass yield, and no oxygen supply with an agitation rate of 250 rpm, in the second stage allowed a successful induction of ethanol production. Fermentation using 60% of HSSL (v/v) as substrate for S. stipitis provided a maximum specific growth rate of 0.07 h−1, an ethanol productivity of 0.04 g L h−1 and an ethanol yield of 0.39 g g−1, respectively. This work showed a successful two-stage aeration strategy as a promising aeration alternative for bioethanol production from HSSL by S. stipitis.

scholarly journals Multistep Structural and Chemical Evaluation of Sugarcane Baggase, Pretreated With Alkali for Enhancing the Enzymatic Saccharification by Cellulase and Xylanase of the Pseudomonas sp. CVB-10 (MK443365) and Bacillus paramycoides T4 (MN370035) Mix-Culture System

2022 ◽  
Vol 9 ◽  
Author(s):  
Soni Tiwari ◽  
Janardan Yadav ◽  
Rajeeva Gaur ◽  
Ranjan Singh ◽  
Tuhina Verma ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Enzymatic Reaction ◽  
Enzymatic Saccharification ◽  
Alkali Pretreatment ◽  
Acid Pretreatment ◽  
Chemical Evaluation ◽  
Naoh Pretreatment ◽  
Structure Changes ◽  
Pretreated Bagasse ◽  
Sem Analyses

The enzymatic saccharification of sugarcane bagasse was significantly increased by alkali pretreatment under mild conditions. The effectiveness of different concentrations of alkali and acid pretreatment of sugarcane bagasse for improving the enzymatic saccharification of lignocellulose has been evaluated. The sugarcane bagasse was characterized to contain 39.52% celluloses, 25.63% hemicelluloses, and 30.36% lignin. After that, sugarcane bagasse was pretreated with 5 and 10% of H2SO4 and NaOH at 121°C for 60 min. FTIR, XRD, and SEM analyses also showed significant molecular and surface structure changes of the sugarcane bagasse with 10% NaOH. Maximum saccharification was 489.5 mg/g from 10% NaOH pretreatment followed by 322.75, 301.25, and 276.6 mg/g from 10% H2SO4, 5% NaOH, and 5% H2SO4, respectively, which were 55.1, 32.0, 27.1, and 20.6 times higher than the that of the control. Cellulase and xylanase produced by Pseudomonas sp. CVB-10 (MK443365) and Bacillus paramycoides T4 (MN370035) were used to hydrolyze the pretreated bagasse, and the optimal condition was determined to be 30 h of the enzymatic reaction with the 3:1 ratio of enzymes under the temperature of 55°C, pH 5.0, and substrate concentration of 3%, leading to celluloses and hemicelluloses conversion in the enzymatic hydrolysis/saccharification that is more proficient.

scholarly journals Robust Optimization of Airplane Passenger Seating Assignments

Aerospace ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 80 ◽  
Author(s):  
R. Milne ◽  
Mostafa Salari ◽  
Lina Kattan
Keyword(s):  
Integer Programming ◽  
Robust Optimization ◽  
Mixed Integer Programming ◽  
Numerical Results ◽  
Mixed Integer ◽  
Two Stage ◽  
Second Stage ◽  
One Stage ◽  
Slack Time ◽  
The One

We present a method that reduces the time it takes to complete the passenger boarding of an airplane. In particular, we describe a two-stage mixed integer programming (MIP) approach, which assigns passengers to seats on an airplane based on the number of bags they carry aboard the plane. The first stage is an MIP that assigns passengers to seats to minimize the time to complete the boarding of the plane. The second-stage MIP also determines seating assignments, while constraining the total boarding time to that determined by the stage-one MIP and maximizing weighted slack times to provide a more robust assignment. Numerical results show that this two-stage approach results in lower average boarding times than the one-stage approach, when the time it takes passengers to walk and sit in their seats is random. Experiments indicate that the magnitude of the improvement is not very sensitive to variations in the slack time weights.

Methods for regression analysis of strong-motion data

1993 ◽  
Vol 83 (2) ◽  
pp. 469-487
Author(s):  
William B. Joyner ◽  
David M. Boore
Keyword(s):  
Strong Motion ◽  
Ordinary Least Squares ◽  
Computational Method ◽  
Two Stage ◽  
Strong Motion Data ◽  
Motion Data ◽  
Weighting Matrix ◽  
Second Stage ◽  
One Stage ◽  
Likelihood Analysis

Abstract We introduce a new computational method for implementing Brillinger and Preisler's (1984, 1985) one-stage maximum-likelihood analysis of strong-motion data. We also reexamine two-stage methods and agree with Masuda and Ohtake (1992) that rigorous analysis requires off-diagonal terms in the weighting matrix for the second-stage regression but note that Masuda and Ohtake failed to account for the earthquake-to-earthquake component of variance. Analysis by Monte Carlo methods shows that both one-stage and two-stage methods, properly applied, are unbiased and that they have comparable uncertainties. Both give the same correct results when applied to the data that Fukushima and Tanaka (1990) have shown cannot be satisfactorily analyzed by ordinary least squares. The two-stage method is more efficient computationally, but for typical problems neither method requires enough time to make efficiency important. Of the two methods, only the two-stage method can readily be used with the techniques described by Toro (1981) and McLaughlin (1991) for overcoming the bias due to instruments that do not trigger.

scholarly journals PENGOLAHAN LIMBAH CAIR TAHU MENGGUNAKAN BIOREAKTOR ANAEROB SATU TAHAP DAN DUA TAHAP SECARA BATCH

2018 ◽  
Vol 7 (1) ◽  
pp. 34-40
Author(s):  
Florence T.N. Silalahi ◽  
Halimatuddahliana ◽  
Amir Husin
Keyword(s):  
Waste Treatment ◽  
Anaerobic Fermentation ◽  
Liquid Waste ◽  
Cow Dung ◽  
Two Stage ◽  
Biogas Yield ◽  
Second Stage ◽  
One Stage ◽  
Batch Bioreactor ◽  
The One

This research aimed to study the effect of one stage and two stage anaerobic fermentation on the performance of bioreactors in tofu liquid waste treatment. This research started with acclimatization that is adaptation process of microorganism derived from cow dung with tofu liquid waste. Acclimatization is carried out in acid condition (pH 5.5) and in neutral condition (pH 7). This is followed by a batch bioreactor operation for 40 days for one stage anaerobic fermentation (pH 7), while for the first stage of the two stage anaerobic fermentation (pH 5.5) lasted two days and proceeds with the second stage of the two stage anaerobic fermentation (pH 7) lasts 38 days The results obtained were COD removal efficiency of 76.6% for one stage anaerobic and 83.05% for two stage anaerobic. While the VFA concentration in the first stage of the two stage anaerobic increased by 33% of the one-stage anaerobic VFA concentration. One-stage anaerobic biogas yield of 0.24 L/g CODconvertedand 0.27 L/g CODconverted for to two stage anaerobic.

Two-Stage Control Charts for High Yield Processes

1997 ◽  
Vol 04 (02) ◽  
pp. 149-165 ◽  
Author(s):  
L. Y. Chan ◽  
M. Xie ◽  
T. N. Goh
Keyword(s):  
False Alarm ◽  
Control Chart ◽  
Control Charts ◽  
High Yield ◽  
Two Stage ◽  
Defective Items ◽  
Second Stage ◽  
Order Of Magnitude ◽  
Cumulative Count

In this paper, a two-stage control chart for monitoring the defective rate of high-yield processes is proposed and studied. The Cumulative Count of Conforming control chart is generalized by using the number of items inspected until two defective items are observed. As this will increase the time to alarm, a two-stage approach combining both schemes is proposed. The occurrence of a defective within n1 items inspected in the first stage indicates that the process is out of control. If no defective occurs within n1 items inspected, the occurrence of two defectives within the next n2 - n1 in the second stage also indicates that the process is out of control. The probability of making a false alarm at the first and second stages are equal to α1 and α2, respectively. This procedure improves the sensitivity of the control chart in detecting shifting of the process defective rate p when p is at the parts-per-million order of magnitude.

Sign in / Sign up

Export Citation Format

Share Document