Microwave-assisted pretreatment of maize distillery stillage with the use of dilute sulfuric acid in the production of cellulosic ethanol

Mikulski, D.; Kłosowski, Grzegorz; Menka, Aleksandra; Koim-Puchowska, Beata

doi:10.1016/j.biortech.2019.01.068

Cited by 62 publications

(27 citation statements)

References 30 publications

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“…The mobile phase was 5 mM H 2 SO 4 with a flow rate of 0.6 mL/min and temperature of 60 • C. The concentration of levulinic acid was determined using the external standard method (ESTD). The separation of the analyzed compounds was carried out in accordance with the instructions of the column manufacturer [50].…”

Section: Hplc Analysismentioning

confidence: 99%

Microwave-Assisted One-Step Conversion of Wood Wastes into Levulinic Acid

Kłosowski¹,

Mikulski²,

Menka³

2019

Catalysts

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This study aimed to evaluate the use of softwood and hardwood waste for the production of levulinic acid by one-stage conversion using microwave radiation combined with acid catalysis. The analysis demonstrated that the type and concentration of the acid used, the concentration of biomass in the reaction mixture and pressure value had the greatest impact on the yield of levulinic acid. The highest efficiency of carbohydrate conversion to levulinic acid, regardless of the type of raw material, was achieved using a pressure of 225 PSI and sulfuric acid as a catalyst. Maximum yield from biomass, ca. 16.5% for cherry wood chips and ca. 25% for pine chips, was obtained using sulfuric acid at a concentration of 1% v/v and 2% v/v, respectively, for the following process parameters: Exposure time 20 min, biomass concentration 3.3%, and the pressure of 225 PSI. The ratio of actual yield to theoretical yield was high: 64.7% ± 4.5% for pine chips and 43.4% ± 1.0% for cherry wood chips. High efficiency of the presented method of biomass conversion to levulinic acid indicates the possibility of its use for waste management in the wood processing industry. High concentration of levulinic acid in the post-reaction mixture allows for cost-effective extraction and purification of the compound.

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Section: Hplc Analysismentioning

confidence: 99%

Microwave-Assisted One-Step Conversion of Wood Wastes into Levulinic Acid

Kłosowski¹,

Mikulski²,

Menka³

2019

Catalysts

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“…However, the use of dilute sulfuric acid together with microwave radiation resulted in ca. 270 mg of glucose per gram of biomass after cellulose hydrolysis [11]. The susceptibility of biomass after hydrotropic treatment to enzymatic hydrolysis using cellulases was also demonstrated in studies on eucalyptus biomass.…”

Section: Selection Of Conditions For Microwave Hydrotropic Extractionmentioning

confidence: 81%

“…Regardless of the type of catalysis, for economic reasons it is advisable to recover acids or bases during the technological process, which is often quite troublesome [3]. Our and other authors' studies clearly pointed to the usefulness of microwave pretreatment in a diluted sulfuric acid environment in the degradation of lignocellulose to simple sugars, which can then be used in bioconversion and biosynthesis processes [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Electromagnetic radiation from 0.3 GHz to 300 GHz quickly heats the biomass (without heating the structural elements of the tank in which it is located) and partially disrupts the hydrogen bonds in the cellulose structure through the oscillating motion of the dipoles. A certain limitation is the presence of overheating zones, called "hotspots", which can generate excessive concentrations of sugar dehydration products that adversely affect yeast's fermentation activity [10][11][12]. The e ciency of baro-thermal treatment of biomass depends on the concentration of the acidic or basic catalyst.…”

Section: Introductionmentioning

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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“…Microwave radiation provides rapid temperature increase and could e ciently break hydrogen bonds. It leads to the disintegration of proteins and the release of TN (Mikulski et al 2019). As been discussed above, free radicals were generated during ultrasonication that could break and deconstruct the cells, and thus lead to release of protein and polysaccharide into the supernatant (Grönroos et al, 2005;Pilli et al, 2011).…”

Section: Resultsmentioning

confidence: 99%

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

Chen

Zhang

et al. 2020

Preprint

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Background: Converting wastewater sludge to lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from wastewater sludge is the low yield (0.10-0.16 g lipid/g dry sludge) due to the low availability of easily uptaken materials (such as soluble monosaccharide and oligosaccharide) in sludge to oleaginous microorganism (Rhodotorula glutinis, Trichosporon oleaginosus, Lipomyces starkeyi). Pretreatments are efficient methods to improve sludge bioavailability. This study is aimed to achieve high lipid production from sludge and high sludge reduction. Results: In this study, it was observed that the soluble chemical oxygen demand (SCOD) had significantly increased after different pretreatment. The SCOD in the supernatant was increased from 32.64 to 180.25 mg/L, 924.16 mg/L, 1029.89mg/L and 3708.31 mg/L after acidic (pH 2 for 2 h), alkaline (pH 12 for 2 h), microwave irradiation (15 min with 5 min interval), and ultrasonication (30 min at 450 W and 20 kHz frequency with 5 s on and 2 s off mode) pretreatment, respectively. Pretreatments have also increased the release of total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as medium for lipid production, and the highest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%. For other pretreatments, the lipid content and sludge reduction were 18.42% and 32.63% in acid pretreatment case, 21.08% and 36.44% in alkaline pretreatment case, and 26.31% and 43.03% in microwave pretreatment case, respectively.Conclusion: It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD) and to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement in lipid yield and sludge reduction. Lipids produced from pretreated sludge were transesterified to biodiesel and the analysis showed that the biodiesel had a similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

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Microwave-assisted pretreatment of maize distillery stillage with the use of dilute sulfuric acid in the production of cellulosic ethanol

Cited by 62 publications

References 30 publications

Microwave-Assisted One-Step Conversion of Wood Wastes into Levulinic Acid

Microwave-Assisted One-Step Conversion of Wood Wastes into Levulinic Acid

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

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

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