Delignification of Aloe Vera Rind by Mild Acid Associated Microwave Pretreatment to Persuade Enhanced Enzymatic Saccharification

Rajeswari, Gunasekaran; Arutselvy, Balakrishnan; Jacob, Samuel

doi:10.1007/s12649-019-00830-7

Cited by 15 publications

(10 citation statements)

References 32 publications

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“…In Aloe vera processing plants, the inner gel is generally separated from the external skin, which accounts for over 30% of the total leaf weight, generating large amounts of waste. In most cases, this agrowaste lacks commercial use and is usually discarded, used as compost or directly incinerated [ 12 ]. Even though there is little information about Aloe vera skin compared to the inner gel, which has been extensively studied, it has been reported that Aloe vera skin could be a promising source of bioactive compounds which might be used in food, food packaging or biomedical applications [ 4 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Valorization of Aloe vera Skin By-Products to Obtain Bioactive Compounds by Microwave-Assisted Extraction: Antioxidant Activity and Chemical Composition

2022

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Aloe vera skin (AVS) is a major by-product of Aloe processing plants all over the world. In this study, response surface methodology was used to optimize microwave-assisted extraction (MAE) of bioactive compounds from AVS. The influence of extraction parameters, such as ethanol concentration (%Et), extraction temperature (T), time (t) and solvent volume (V), on extraction yield (Y), total phenolic content (TPC), antioxidant activity (DPPH and FRAP methods) and aloin content, was studied. Optimum extraction conditions were determined as 80% ethanol, 80 °C, 36.6 min and 50 mL and optimized extracts showed interesting contents of polyphenols and antioxidant performance. The phenolic profile was determined by HPLC-DAD/MS and some major phenolic compounds, such as aloin A, aloin B, aloesin, aloe-emodin, aloeresin D, orientin, cinnamic acid and chlorogenic acid, were quantified while eight other compounds were tentatively identified. Moreover, structural and thermal properties were studied by FTIR and TGA analyses, respectively. The obtained results suggested the potential of AVS as a promising source of bioactive compounds, thus increasing the added value of this agricultural waste.

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Section: Introductionmentioning

confidence: 99%

Valorization of Aloe vera Skin By-Products to Obtain Bioactive Compounds by Microwave-Assisted Extraction: Antioxidant Activity and Chemical Composition

2022

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“…For pretreatment in combination with microwave radiation, sulfuric acid, ionic liquids, or basic salts with orthophosphoric acid are most often used. Microwaves together with 0.5% v/v sulfuric acid reduced the concentration of lignins in aloe biomass by up to 66% (Rajeswari et al 2020 ). The combined action of ionic liquids together with microwave radiation at 130 °C resulted in a nearly 80% reduction in lignin concentration in Miscanthus biomass and birch wood (Kohli et al 2020 ).…”

Section: Discussionmentioning

confidence: 99%

Microwave-assisted hydrotropic pretreatment as a new and highly efficient way to cellulosic ethanol production from maize distillery stillage

Mikulski

Kłosowski

2021

Appl Microbiol Biotechnol

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Aim of the study was to assess the suitability of the combined use of microwave radiation and sodium cumene sulfonate under optimized process conditions for the preparation of maize stillage biomass as a raw material for the production of cellulosic ethanol. The key parameter guaranteeing a high level of lignin removal from biomass (ca. 44%) was concentration of hydrotrope. Even at high biomass concentration (16% w/v) and a cellulase enzyme dose of about 4 filter-paper units/g, maize stillage biomass subjected to microwave-assisted hydrotropic pretreatment was highly susceptible to enzymatic degradation, which resulted in 80% hydrolysis yield. It is possible to obtain a fermentation medium with a very high glucose concentration (up to 80 g/L), without fermentation inhibitors and, as a consequence, to reach a very high level of sugar conversion to ethanol (concentration above 40 g/L), even as much as 95% of theoretical yield. Microwave hydrotropic treatment with sodium cumene sulfonate is a very effective way to prepare waste maize stillage biomass for the production of cellulosic ethanol. The degradation of the lignocellulose structure by the simultaneous use of microwaves and hydrotropes ensured a high degree of conversion of structural polysaccharides to bioethanol. The method provides a high level of enzymatic degradation of cellulose, leading to a medium with high content of released sugars suitable for bioconversion, which is in line with assumptions of the second-generation ethanol production technology. Key points • Microwave-assisted hydrotropic pretreatment is a new way to cellulosic ethanol production. • Microwave-assisted hydrotropic delignification removes 44% of lignin from biomass. • No fermentation inhibitors are obtained after microwave-assisted hydrotropic pretreatment. • High ethanol concentration (above 40 g/L) and fermentation yield (95% of theoretical yield) from biomass after microwave-assisted hydrotropic pretreatment.

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“…For pretreatment in combination with microwave radiation, sulfuric acid, ionic liquids or basic salts with phosphoric acid are most often used. Microwaves together with 0.5% v/v sulfuric acid reduced the concentration of lignins in aloe biomass by up to 66% [22]. The combined action of ionic liquids together with microwave radiation at 130ºC resulted in a nearly 80% reduction in lignin concentration in Miscanthus biomass and birch wood [24].…”

Section: Selection Of Conditions For Microwave Hydrotropic Extractionmentioning

confidence: 99%

“…Microwaves are also used as a factor supporting deligni cation with acids and bases, ionic liquids or organic solvents. With properly selected process conditions, microwave treatment combined with the use of dilute sulfuric acid reduced the lignin content in Aloe vera biomass by more than 50% [22]. Diluted sodium hydroxide together with microwave radiation also successfully deligni ed the biomass of Prosopis juli ora (lignin content reduction up to 70%) [23].…”

Section: Introductionmentioning

confidence: 99%

“…The biomass was then rinsed with 150 mL of hot distilled water to remove residual extraction solution, and dried to constant weight (DW) at 130 °C using a moisture analyzer. The biomass extractives were calculated based on the difference in sample weight before and after hydrotropic extraction[22]. The analysis was performed in 9 replications to obtain enough biomass necessary to calculate the biomass extractives and to obtain the raw material for the analysis of lignocellulose composition and to carry out the enzymatic hydrolysis process.…”

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confidence: 99%

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Microwave-assisted hydrotropic pretreatment as a new and highly efficient way to cellulosic ethanol production from maize distillery stillage

Mikulski

Kłosowski

2020

Preprint

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Background: The development of the second generation ethanol production technology requires new, highly effective methods of pretreatment of lignocellulosic biomass, which reduces lignin content, eliminates fermentation inhibitors, and makes the biomass susceptible to hydrolysis using cellulolytic enzymes. New pretreatment methods should be adapted to the processing of lignocellulosic waste biomass from various industries. One of the problems is the management of grain stillage, which is waste from the production of first generation ethanol.Results: The aim of the study was to assess the suitability of the combined use of microwave radiation and sodium cumene sulfonate under optimized process conditions for the preparation of maize stillage biomass as a raw material for the production of cellulosic ethanol. The key parameter guaranteeing a high level of lignin removal from biomass (ca. 44%) was the concentration of hydrotrope. The highest organic matter extraction from biomass (67.00±1.68%) was observed for 20% v/v sodium cumene sulfonate, ca. 117 PSI (microwave heating) and 30 min exposure time. Even at high biomass concentration (16% w/v) and a cellulose enzyme dose of about 4 FPU/g, maize stillage biomass subjected to microwave-assisted hydrotropic pretreatment was highly susceptible to enzymatic degradation, which resulted in 80% hydrolysis yield. The stillage biomass processed in this way is a very good raw material for the production of cellulosic ethanol. It is possible to obtain a fermentation medium with a very high glucose concentration (up to 80 g/L), without fermentation inhibitors (such as 5-HMF, furfural, lignin degradation products) and, as a consequence, to reach a very high level of sugar conversion to ethanol, even as much as 95% of theoretical yield.Conclusions: Microwave hydrotropic treatment with sodium cumene sulfonate is a very effective way to prepare waste maize stillage biomass for the production of cellulosic ethanol. The method provides a high level of enzymatic degradation of cellulose, leading to a medium with high content of released sugars suitable for bioconversion, which is in line with the assumptions of the second generation ethanol production technology.

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Delignification of Aloe Vera Rind by Mild Acid Associated Microwave Pretreatment to Persuade Enhanced Enzymatic Saccharification

Cited by 15 publications

References 32 publications

Valorization of Aloe vera Skin By-Products to Obtain Bioactive Compounds by Microwave-Assisted Extraction: Antioxidant Activity and Chemical Composition

Valorization of Aloe vera Skin By-Products to Obtain Bioactive Compounds by Microwave-Assisted Extraction: Antioxidant Activity and Chemical Composition

Microwave-assisted hydrotropic pretreatment as a new and highly efficient way to cellulosic ethanol production from maize distillery stillage

Microwave-assisted hydrotropic pretreatment as a new and highly efficient way to cellulosic ethanol production from maize distillery stillage

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