INTRODUCTION
Rationale
Cassava is the third-largest source of food carbohydrates globally and serves as a vital staple for over half a billion people in developing countries It is primarily processed into chips, pellets, and starch According to FAOSTAT (2013), Thailand is a key player in the cassava market, being the world's leading exporter of cassava chips and starch, while also ranking as the second-largest producer after Nigeria in 2016.
Fig 1.1 Top 10 country production of cassava in the world (FAO, 2016)
Cassava roots are highly rich in starch, serving as the primary material for the cassava starch industry When processed into a powdery extract, known as cassava starch or tapioca, approximately 3.5 to 4.8 tons of cassava roots yield 1 ton of cassava starch The by-products of this process include cassava peel, which amounts to 50-160 kg, and cassava pulp, ranging from 1.0 to 2.8 tons This significant quantity of cassava pulp represents a valuable but underutilized solid residue, typically sold at low prices for animal feed Enhancing the utilization of cassava pulp could improve efficiency and create additional value from cassava starch production.
Cassava pulp can be transformed into high-value products, with significant scientific literature available on its characteristics and composition This byproduct is utilized in various applications, including the production of ethanol, hydrogen, biogas, and organic fertilizer However, there is limited analysis regarding the potential for sugar production from cassava pulp.
Cassava pulp is composed of approximately 50–70% starch, 20–30% lignocellulose, and small amounts of protein and fat, making it unsuitable for animal feed due to its low protein content Despite its high organic matter, the direct hydrolysis of cassava pulp is inefficient because of the recalcitrant properties of lignocellulosic materials (LCMs) and the entrapment of starch within the cell walls Hemicellulose and lignin form a protective sheath around cellulose, while the high crystalline structure of cellulose acts as a barrier to hydrolysis, hindering degradation by the surrounding environment Therefore, pretreatment is a crucial step to enhance hydrolysis efficiency.
The purpose of pretreatment is to break down the cell wall of lignocellulosic materials (LCMs), which increases the accessible surface area and enhances the recrystallization of cellulose, solubilization of hemicellulose, and removal of lignin This breakdown facilitates easier access to starch in cassava pulp during the hydrolysis step, thereby improving the overall hydrolysis process of cassava pulp for subsequent stages.
There are many previous researches that use pretreatment methods on LCMs There were four types of pretreatment: (1) physical pretreatment, (2) chemical
There are three main types of pretreatment methods: physical, physico-chemical, and biological, each with distinct mechanisms, advantages, and disadvantages The choice of method depends on the material and desired outcome Liquid hot water (LHW) pretreatment, which combines physical and chemical processes without the use of catalysts, shows great promise This technique effectively removes most hemicellulose, enhances cellulose hydrolysis, and minimizes sugar degradation caused by inhibitors, making it particularly suitable for extracting sugar from cassava pulp To optimize LHW pretreatment, it is crucial to manage various factors, including reaction time, temperature, pressure, and the ratio of materials, to prevent the formation of inhibitors and ensure high sugar recovery.
This study aims to look at the effects of temperature and reaction time of liquid hot water pretreatment for sugar production from cassava pulp.
Problem statement and justification
Cassava was mainly cultivated in tropical areas and used as food and feedstock
Thailand consumes around 10 million tons of fresh cassava tubers annually, primarily as a starch staple During the starch extraction process, grated cassava is separated into starch granules and fibrous residual materials, with the latter, known as cassava pulp, constituting about 10–30% of the original tubers by weight This results in the tapioca starch industry generating at least one million tons of cassava pulp each year Reports indicate that cassava pulp contains up to 60% starch (on a dry weight basis) along with cellulosic fiber, highlighting its significant organic compound content This abundant and cost-effective material has garnered interest for conversion into high-value products such as ethanol, sugar, hydrogen, biogas, and organic fertilizer.
Recently, there has been more interest on using pretreatment step before apply hydrolysis step Because it is easily applied, cheaper and more efficient direct
The primary goal of pretreatment methods for cassava pulp is to break down the cell walls of lignocellulosic materials (LCMs), thereby increasing the accessible surface area for easier starch hydrolysis This enhancement facilitates more effective hydrolysis of cassava pulp in subsequent processing steps Selecting the appropriate pretreatment method for industrial application is crucial from an economic perspective, as it must be cost-effective at a commercial scale Key considerations include capital and operational costs, the loading of LCMs, high carbohydrate recovery, and minimizing sugar degradation into inhibitors Although various pretreatment methods have been explored, only a few have proven to be economically viable for industrial use The most notable methods include steam explosion, liquid hot water, concentrated and diluted acid pretreatment, and biological pretreatment.
Acid pretreatment of lignocellulose is aimed at solubilizing hemicellulose to enhance cellulose accessibility This process can hydrolyze amorphous cellulose regions and partially remove lignin, although lignin solubility remains low While both concentrated (30-70%) and diluted (below 4%) acids are used, diluted acid is preferred due to its lower toxicity, reduced corrosiveness, and lower equipment costs The integration of diluted acid pretreatment with temperature adjustments—either low (below 120°C) or high (above 180°C)—can achieve reaction rates comparable to concentrated acid, with longer reaction times at lower temperatures (30-90 minutes) and shorter times at higher temperatures (1-5 minutes) Common acids employed include hydrochloric, nitric, and phosphoric acids, but sulfuric acid is favored for its cost-effectiveness and efficiency Despite the advantages of high hemicellulose hydrolysis efficiency and improved cellulose accessibility, drawbacks include sugar decomposition into inhibitors such as furfural, hydroxymethylfurfural, and acetic acid, alongside expenses related to equipment, maintenance, and the neutralization process post-pretreatment.
Steam explosion or auto hydrolysis, this pretreatment method was one of the most commonly used for LCMs During the pretreatment, LCMs are subjected to the
High-pressure steam treatment (0.69-4.83 MPa) at elevated temperatures (160-260℃) for a specific duration effectively disrupts the lignocellulose structure Following this process, a rapid reduction in pressure leads to the hydrolysis of the acetyl groups in hemicellulose, creating an acidic environment This acidic condition facilitates the hydrolysis of ether bonds, resulting in the breakdown of hemicellulose, partial lignin hydrolysis, and an increase in surface area.
The pretreatment method of steam explosion shows promise for commercial applications due to its low energy consumption, absence of chemicals, and cost-effectiveness in downstream neutralization processes However, this method can produce inhibitors through sugar degradation, leading to significant sugar loss when water is used for their removal To address this issue, research has focused on optimizing steam explosion conditions to minimize inhibitor formation.
Liquid hot water (LHW) pretreatment, also known as hydrothermal pretreatment, utilizes high pressure to maintain water in a liquid state at temperatures between 140-240°C The primary goal of LHW is to solubilize hemicellulose, thereby enhancing access to the cellulose structure This process operates similarly to steam explosion, where hydronium ions generated from water catalyze glycosidic bonds During LHW, water infiltrates the cell wall, hydrating cellulose, solubilizing hemicellulose, and partially removing lignin, which increases the surface area of the biomass Following pretreatment, the resulting hydrolysate can be directly used in hydrolysis or fermentation, as it produces minimal inhibitors.
The comparison between steam explosion and low hydrothermal (LHW) pretreatment reveals that LHW offers higher sugar recovery and lower inhibitor formation, making it advantageous However, the process requires a significant amount of water, leading to low sugar concentration and high energy consumption Consequently, implementing a hydrolysis step after LHW pretreatment is essential for maximizing sugar extraction from cassava pulp Furthermore, LHW has been effectively applied to cassava pulp for producing value-added products, such as combining pretreatment with fermentation to convert its components into ethanol.
6 sugar recovery from wheat straw by way using combination of LHW and emzyme hydrolysis [9] Several study of LHW on LCMs were observed such as wheat straw
[40] , sugarcane bagasse [41], soybean straw [42], corn fiber [43], rice straw [44] and soy hulls [45]
To achieve maximum sugar yield, the optimization of various factors in LHW pretreatment was analyzed This study specifically focused on the impacts of temperature and reaction time on sugar production through LHW processes.
Objectives
To assess temperature and reaction time of LHW on Cassava pulp
To prepare the substrate for hydrolysis step on sugar production
Hypothesis
Liquid hot water pretreatment could be hydrolysis of cassava pulp for sugar production
Expect benefits
To extend the knowledge regarding effect of the temperature and reaction time of LHW for the high sugar production
To improve the substrate is easily access in further step hydrolysis
METHODOLOGY
Materials
1 Cassava pulp from Choncharoen company, Bangkok, Thailand
3 Zip bags, Nylon bags, Fiber bags
4 Hot air oven (Memmert, UFE600, Germany)
5 Vortex mixture (vortex genie, Scientific Industries, USA)
6 UV-Visible spectrophotometer (UV - Pharo 100, Spectroquant, Germany)
7 Fume hood (Well model 2000, Thailand)
9 Pressure Reactor (Parr Reactor 4848, America)
10 Automatic fiber (Fibretherm ft12, Gerhardt)
12 Centrifuge (PLC - 05, Germany Industrial crop, Taiwan
13 Laboratory instruments such as a micropipette, cuvette, pipette tip, crucible, beaker, petri dish, hycon plastic, dispensing bottle, Erlenmeyer flask, desiccator
14 The chemical used in the experiment: Sulfuric acid 98 %, Phenol, Sodium hydroxide (Sigma Chemicals, NJ, USA), Red Metheny, mixed catalyst digestion tablets (Potassium sulfate and Selenium), Boric acid were used for protein analysis Petroleum ether was used for fat content analysis Sulfuric acid, sodium hydroxide (Sigma Chemicals, NJ, USA), Sodium hydroxide, Sodium postassium tartrate, Dinitrosalicylic acid , Sodium pyrosulfite
Methods
Cassava pulp (CP), a byproduct of cassava starch processing, was sourced from Choncharoen in Bangkok, Thailand The pulp was milled and screened to a particle size of 8-18 mesh, then dried in a hot air oven at 55°C until it reached a constant weight, which took approximately 10 hours Following the drying process, the CP was stored in zip bags at room temperature for preservation.
Fig 2.1 Cassava pulp after dry 2.2.2 Analytical methods
Characterization as: Moisture, Ash, Total solid, Volatile solid, Protein, Lipid were determined by AOAC 2000
1 Total sugar by Phenol-Sulfuric acid method [47] (Dubois, 1956 )
2 Reducing sugar by DNS method [48] (Miller, 1959)
3 Starch content by enzymatic method [49] (Ref )
4 Lignocellulose (NDF, ADF, ADL) by Detergent method [50] (Van
1 Place the crucible in the furnace at 550°C overnight to ensure that impurities on the surface of the crucible are burned off
2 Cool the crucible in the desiccator (30 min)
3 Weigh the crucible to 4 decimal places
4 Weigh about 1- 2 g sample into the crucible Dry for 3 hr at 105 °C
5 Cool down in the desiccator (30 min)
6 Re-Weigh and calculation moisture content
Where: W1: Weigh (g) of sample before dry
W2: Weigh (g) of sample after dry
1 Place the crucible in the furnace at 550°C overnight to ensure that impurities on the surface of the crucible are burned off
2 Cool the crucible in the desiccator (30 min)
3 Weigh the crucible to 4 decimal places
4 Weigh about 1- 2 g sample into the crucible Dry for 3 hr at 105°C
6 Cool down in the desiccator for 30 min
7 Weigh the ash with crucible when the sample turns to gray and calculation of ash content
Where w1: weight of crucible; w2: weight of crucible and sample; w3: weight of sample
2.2.2.3 Analyze protein by the Kjeldahl method
Weigh approximately 1 g of sample (to a precision of 2 decimal places) using a weighing paper Transfer the sample into Kjeldahl flask tube and add one small spoon of mixed catalyst digestion tablets
Protein analysis has 3 steps: Homogeneous sample, distillation and titration
To initiate the analysis, add 20 mL of 98% sulfuric acid solution to each Kjeldahl flask containing the sample and mixed catalyst, then digest the sample at 360 °C for approximately 180 minutes Next, prepare a titration flask with 20 mL of 0.1 mol/L sulfuric acid and a few drops of Tashiro indicator, raise the platform, and commence the distillation process Once distillation is complete, titrate the contents of the receiver flask with 0.1 mol/L sulfuric acid until reaching the neutral endpoint, and record the volume of sulfuric acid used Additionally, perform a blank titration to observe the color change of the Tashiro indicator.
A: volume (ml) of 0.1 N H2SO4 used sample titration B: volume (ml) of 0.1 H2SO4 used blank titration N: normality of H2SO4
14.007: atomic weight of nitrogen E: Empirical factor
2.2.2.4 Analyze lipid by Soxhlet method
1 Place the beakers and lid in the incubator at 105°C about 5 hr and weight of beakers
2 Weigh about 1 g of the sample to paper filter and wrap
3 Take the sample into extraction thimble and transfer into soxhlet
4 Fill petroleum ether about 250 mL into the round bottom flask and take it on the heating mantle
5 Connect the soxhlet apparatus and turn on the water to cool them and then switch on the heating mantle
6 Heat the sample about 14 hr (heat rate of 150 drops/min)
7 Evaporate the solvent by hot air oven at 105°C until the solvent is completely evaporated and bottles are completely dry
8 After drying, transfer the bottle with a partially covered lid to the desiccator to cool Re-weighs the bottles and it dried content
Where w1: weight of beaker initial, gram; w2: weight of fat and beaker, gram; w3: weight of sample initial, gram
2.2.2.5 Analyze Starch content by hydrolysis method
1 Accurately weigh 75- 100 mg sample in duplicate into 100 mL beaker Samples should contain up to 100 mg starch Alternatively, filter 80% Et
OH extracted a 0.2 g sample using Whatman filter paper, transferring the entire paper into a beaker Additionally, an empty beaker was included to serve as a reagent blank for the experiment.
2 Add 20 mL of dH2O to the sample and stir with a magnetic stir bar
3 Add 0.1 mL heat-stable -α- amylase to sample and water and stir with a magnetic stir bar
4 Cover beaker with Aluminum foil and place in 90C in water bath for 1 hour Remove beaker from water bath and cool on bench for 15 minutes
5 Filter samples through glass wool plugs in funnels into 100 mL volumetric flasks Rinse the beaker, the funnel and glass wool thoroughly with d H2O Adjust filtered solutions to volume with d H2O Mix solutions thoroughly through repeated inversion and shaking of capped or stoppered flasks
6 Pipette a 1 mL aliquot of each sample into individual 50 mL volumetric flasks
7 Add 8 mL of 0.1 M sodium acetate buffer (pH ~ 4.5) to each flasks
8 Add 50 𝜇L of amyloglucosidase Gently swirl flask to mix
9 Incubate flasks in 60°C water bath for 30 minutes
10 Bring sample to volume with d H2O
11 Assay the hydrolysed sample for glucose to determine starch content
2.2.2.6 Analyze Lignocellulose (NDF, ADF, ADL) by Detergent method
2 Add 100 mL Neutral detergent and 0.2 mL heat- Stable -α amylase
4 After 1 hr measured from the time boiling began, filter sample
5 Thoroughly rinse the beaker into the filter with boiling dH20
6 Rinse the residue 2x with boiling dH20
7 Rinse the residue 2x with acetone
8 Dry of residue after filter sample (AOAC)
9 Determine ash of residue after filter sample (AOAC)
1 Dry the sample at 55C (85% dry matter)
2 Weigh 1 g (W1) sample into Berzelius beaker
3 Add 100 mL acid-detergent solution at room temperature
4 Place beaker on heater under the cold water condenser Heat to boiling in 5-
10 min; reduce heat to avoid foaming as boiling begins
5 Reflux 60 min from onset of boil
6 After about 30 min, Remove beaker, swirl, and filter through tare fritted glass crucible, using minimal vacuum
7 Rinse twice with boiling (95-100C) water
8 Rinse twice with 30-40 mL acetone
9 Dry 3 hr or overnight in forced-air oven (105C) and weight
To conduct the acid hydrolysis process, place fiber bags containing samples into a 100 mL beaker and add concentrated H2SO4 (72%) Stir the fiber bags every 10 minutes for a total duration of 3 hours to ensure thorough mixing Afterward, rinse the samples with water and transfer the filter bags to an oven, drying them overnight at 105°C Finally, heat the dried samples in a furnace at 550°C for 3 hours to complete the procedure.
2.2.2.7 Analyze Total Sugar by Phenol- Sulfuric acid method
The method for determining total sugar is adapted from Dubois (1956) with modifications It involves mixing 1 mL of an appropriately diluted sample, previously hydrolyzed after LHW, with 1 mL of 2% phenol and 5 mL of concentrated H2SO4 The mixture is then thoroughly vortexed and incubated at room temperature (25°C).
30 min The absorbance was measured at 490 nm using a spectrophotometer and the results were compared glucose standard curve
Additional dilution was done if the absorbance value measured was over the linear range of the standard curve
2.2.2.8 Analyze Reducing Sugar by DNS method
The setup we used for determined Reducing sugar by DNS method from Miller,
In 1959, a 1 mL sample, appropriately diluted following hydrolysis after LHW, was combined with 1 mL of DNS reagent and heated in a boiling water bath at 80°C for 15 minutes The mixture was then cooled in an ice bath for 15 minutes, followed by the addition of 5 mL of distilled water, which was thoroughly mixed using a Vortex After incubating the solution at room temperature (25°C) for 10 minutes, the absorbance was measured at 570 nm with a spectrophotometer, and the results were compared to a glucose standard curve.
Additional dilution was done if the absorbance value measured was over the linear range of the standard curve
2.2.3 Liquid hot water (LHW) pretreatment
Details of the LHW pretreatment are described elsewhere (Yu et al., 2012,
2010) About 5 g of the CP (5% w/v in water) was put into the reactor, which was sealed and heated to the reaction temperature with the magnetic agitator operating at
500 rpm The reaction pressure was controlled by the addition of nitrogen [51, 52]
After the reaction was completed, the hydrolysate was collected, and the reactors were quickly cooled to halt the reaction The solution was then filtered to separate the hydrolysate from the solid residue, which was subsequently recovered from the reactor.
15 using for the measurement of weight loss The hydrolysate after LHW was analyzed for reducing sugar and total sugar as describe in 2.2.2.7 and 2.2.2.8
2.2.3.2 Statistical design of experiments of LHW pretreatment
Table 2.2 outlines the experimental design conditions, specifying that the temperature and reaction time for the LHW process are set between 140°C and 180°C, and 0 to 30 minutes, respectively This study utilizes room temperature as a control and compares it to autoclave conditions, which are commonly employed methods for pretreating CP.
Hydrolysate obtained after LHW pretreatment were analyzed to determine total sugar and reducing sugar.
Table 2.2 Following the LHW pretreatment
RESULTS AND DISCUSSION
Characterization of substrate
Chemical composition of Cassava Pulp used the analytical and calculation The results were showed in table 3.1 (Each experiment were replicated at least 3 times)
Table 3.1 Chemical composition of cassava pulp in % dry
Fig 3.2 The result of characterization of cassava pulp in % dry weigh basis
MoistureAshProteinCrude Fat
Table 3.1 presents the chemical composition of cassava pulp on a dry weight basis, revealing that cassava pulp is rich in organic compounds, with starch constituting approximately 48% of its dry weight The lignocellulose composition includes about 19% cellulose, 10% hemicellulose, and 2% lignin However, the protein content in cassava pulp is low, making it unsuitable for animal feedstock.
From there, it showed that starch and LCMs were the main component of Cassava pulp which could be hydrolysis for sugar production with high efficiency
[54] Due to, cassava pulp material has component which was suitable for this study.
Effect of temperature and reaction time on solid remaining
Table 3.2 presents the amounts of solid residues and hydrolysate resulting from low-temperature hydrothermal treatment (LHW), revealing solid remaining percentages between 21.7% and 95.1% The findings indicate that harsher conditions lead to greater solubilization, with reaction time and temperature significantly affecting solid residue levels For instance, the solid residue reached a maximum of 95.1% under control conditions, while the minimum was recorded at 21.7% following treatment at 180°C for 15 minutes The variation in solubilization of water-soluble biomass components into hydrolysate is closely linked to the pretreatment conditions, aligning with previous studies by Qiang Yu et al (2013) and Perez et al (2008).
After that, the hydrolysate was collected to determine total sugar and reducing sugar
Effect of temperature and reaction time on total sugar and reducing sugar of
Table 3.2 Results of substrate after LHW pretreatment
Run Process conditions Collected after LHW
Table 3.3 Results of reducing sugar and total sugar
Table 3.3 displays the results of total and reducing sugar content in hydrolysate Most experiments indicate that an increase in temperature and reaction time correlates with higher levels of both total and reducing sugars However, the release of sugars from raw materials during pretreatment does not consistently yield the expected results.
Run Process conditions Hydrolysate after LHW
Reducing sugar (mg RS/gCP)
20 derive into sugar recovery Due to, the sugar degradation at high temperature and turning these components into lower molecular weight products, such as furfural, hydroxyl methyl furfural, inhibitors [55]
Under all tested conditions, glucose was detected in the hydrolysate, indicating its source is not solely from lignocellulosic materials (LCMs) The presence of grain starch in the cassava pulp may contribute to this easily-solubilized glucose At control conditions, the reducing sugar was measured at 5.8 mg RS/g CP, while autoclave conditions showed an increase to 12 mg RS/g CP The accompanying chart illustrates the varying amounts of reducing sugar under different low-temperature hydrolysis (LHW) conditions.
Fig 3.2 The content of reducing sugar in hydrolysate after LHW pretreatment
An analysis of the reducing sugar content in hydrolysate obtained after pretreatment revealed that extending the reaction time from 0 to 30 minutes at 140°C significantly increased the yield from 1 mg to 41.9 mg Furthermore, when the temperature was raised to 160°C for the same duration, the reducing sugar content tripled, demonstrating the impact of both time and temperature on sugar yield.
The study observed that reducing sugar content increased significantly with temperature and reaction time during liquid hot water (LHW) treatment, ranging from 21 mg at 140°C for 30 minutes to 130.5 mg at 160°C for the same duration When the temperature was raised to 180°C, reducing sugar levels surged from 55.8 mg to 302.9 mg over a 30-minute period Notably, at 180°C, the reducing sugar content at 15 minutes was four times higher than at the initial 0-minute mark, while extending the time from 15 to 30 minutes resulted in only a slight increase from 260 mg to 302.9 mg These findings indicate that the relationship between temperature and time in LHW treatment is not linear.
The analysis of total sugar (TS) revealed that under control conditions, the total sugar content was approximately 37.2 mg, while it increased to 211.7 mg under autoclave conditions Additional results of the hydrolysate obtained after pretreatment are illustrated in Figure 3.3.
Fig 3.3 The content of total sugar in hydrolysate after LHW pretreatment
The total sugar content of hydrolysate increased progressively with both temperature and reaction time, ranging from 0 to 30 minutes at temperatures between 140°C and 180°C Notably, at 140°C, there was a significant increase in total sugar levels.
The study revealed a recovery yield ranging from 229 mg at 15 minutes to 552 mg at 30 minutes, indicating that extended reaction times enhance total sugar recovery Additionally, at 160°C, total sugar recovery increased with longer reaction times In contrast, at 180°C, the total sugar value significantly changed from 762 mg at 15 minutes as the reaction time increased.
452 mg at 30 min All of the conditions, a maximum total sugar recovery value 762 mg of content was reached at 180°C for 15 minutes When the reaction time increased
In just 30 minutes, a significant sugar loss of over 302 mg was observed under consistent temperature conditions This reduction in total sugar in the hydrolysate suggests that the degradation of sugar is accelerated, resulting in the formation of lower molecular weight compounds and the generation of inhibitors These changes occur under harsh conditions characterized by high temperatures and extended residence times.
During pretreatment, high temperatures can degrade sugar, leading to the formation of lower molecular weight products, including furfural, hydroxymethylfurfural, acetic acid, and various inhibitors, a finding consistent with several reports.
CONCLUSION AND RECOMMENDATION
Conclusion
Through our research at the Phytobioactive and Eco- Waste Laboratory, Bangkok, Thailand, we make the following conclusions:
The sugar recovery from hydrolysate after LHW pretreatment significantly exceeded that of the control and autoclave conditions, indicating effective hydrolysis of cassava pulp's LCMs and starch into sugar The sugar content varied based on temperature and reaction time under saturated vapor pressure, with higher temperatures and longer reaction times not always leading to increased sugar yields Optimal solubilization occurred under harsher conditions only up to a certain threshold, with the best results achieved at 180°C for 15 minutes, yielding 760 mg of total sugar and 260 mg of reducing sugar.
Recommendation
Although, the sugar recovery in hydrolysate (after LHW) was high, but the large amount of water was used during LHW pretreatment, causing low sugar concentration difficult for collection
To achieve maximum sugar production from cassava pulp, a two-stage process is essential The initial pretreatment stage focuses on optimizing hydrolysate recovery, while the subsequent stage is dedicated to maximizing glucose recovery The combination of low-temperature hydrothermal (LHW) pretreatment followed by hydrolysis or fermentation is identified as an effective method for enhancing sugar production Hydrolysis is crucial for converting polysaccharides into monomers, and the pretreatment step significantly improves sugar yield during hydrolysis.
This study focused solely on the pretreatment step, highlighting the need for extended hydrolysis or fermentation in subsequent phases By doing so, it is possible to improve sugar production efficiency and maximize the utilization of sugar derived from cassava pulp waste.
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Table A1 The temperature and reaction time value of LHW were delimited within a range of 140°C - 180°C and 0 - 30 min for total sugar and reducing sugar
All values are expressed as dried basis (mean ± SD) Mean data three replicates Different data in the same column mean significant difference (p ≤ 0.05)
Table A2 Effect of liquid hot water pretreatment at 140 o C with various reaction time conditions for total sugar and reducing sugar
Sugar production Reducing sugar Total sugar
All values are expressed as dried basis (mean ± SD) Mean data three replicates Different data in the same column mean significant difference (p ≤ 0.05)
Table A3 Effect of liquid hot water pretreatment at 160 o C with various reaction time conditions for total sugar and reducing sugar
Sugar production Reducing sugar Total sugar
All values are expressed as dried basis (mean ± SD) Mean data three replicates Different data in the same column mean significant difference (p ≤ 0.05)
Table A4 Effect of liquid hot water pretreatment at 180 o C with various reaction time conditions for total sugar and reducing sugar
Sugar production Reducing sugar Total sugar
All values are expressed as dried basis (mean ± SD) Mean data three replicates
Different data in the same column mean significant difference (p ≤ 0.05).