Fed-batch Simultaneous Saccharification Research Articles

Hydrodynamic cavitation-assisted acid pretreatment and fed-batch simultaneous saccharification and co-fermentation for ethanol production from sugarcane bagasse using immobilized cells of Scheffersomyces parashehatae

A new alternative for hydrodynamic cavitation-assisted pretreatment of sugarcane bagasse was proposed, along with a simultaneous saccharification and co-fermentation (SSCF) process performed in interconnected columns. Influential variables in the pretreatment were evaluated using a statistical design, indicating that an ozone flow rate of 10 mg min−1 and a pH of 5.10 resulted in 86 % and 72 % glucan and xylan hydrolysis yields, respectively, in the subsequent enzymatic hydrolysis process. Under these optimized conditions, iron sulfate (15 mg L−1) was added to assess Fenton pretreatment, resulting in glucan and xylan hydrolysis yields of 92 % and 71 %, respectively, in a material pretreated for 10 min. In SSCF, ethanol volumetric productivities of 0.33 g L−1 h−1 and of 0.54 g L−1 h−1 were obtained in batch and fed-batch operation modes, achieving 26 g L−1 of ethanol in 48 h in the latter mode.

Enhanced cellulosic ethanol production via fed-batch simultaneous saccharification and fermentation of sequential dilute acid-alkali pretreated sugarcane bagasse

This study reports high gravity fed-batch simultaneous saccharification and fermentation (FB-SSF) of sequentially pretreated sugarcane bagasse (SCB) for enhanced bioethanol by employing multiple inhibitor tolerant Kluyveromyces marxianusJKH5 C60. FB-SSF with intermittent feeding of SCB (total 20 % solid loading) and enzyme (total dose of 20 FPU/g) at 6 and 12 h resulted in superior bioethanol production at42 °C. Under optimizedlab-scaleFB-SSF, the maximum ethanoltiter, efficiency and productivities were73.4 ± 1.2 g/L,78 % and 3.0 g/L/h, respectively, after 72 h in presence of inhibitors (acetic acid, furfural, and vanillin at 3, 1, and 1 g/L, respectively). Furthermore, pentose rich dilute acid hydrolysate of SCB was subjected to fermentation by Pichia stipitis NCIM 3499, resulting in ethanol titer of 6.8 g/L. Overall ethanol yield during the developed process was 260.1 g/kg native SCB, which proves industrial potential of the developed bioethanol conversion process.

High-Solid Loading Enzymatic Hydrolysis of Waste Office Paper for poly-3-hydroxybutyrate Production Through Simultaneous Saccharification and Fermentation

Waste paper holds great potential as a substrate for the microbial production of bioplastic (Poly-3-hydroxybutyrate (PHB)). This study aimed to produce PHB by utilizing office paper as a substrate using Cupriavidus necator through batch and fed-batch simultaneous saccharification and fermentation (SSF) approach. For the batch experiment, different loadings of shredded office paper (3, 5 and 10%) with two different pretreatments H2O2 (OPH) and H2O2 and Triton X-100 (OPTH) were carried out. For the fed-batch experiment, paper loading started with 3% and two more additions were made at 36 and 84 h. Both experiments were conducted at 30 °C, 200 rpm and pH 7 using 55.5 FPU/g of cellulase and 37.5 CBU/g of β-glucosidase with a fixed amount of nitrogen source. High PHB yield was observed with OPH in all loadings, though the OPHT showed a better hydrolysis. Maximum PHB yield (4.27 g/L) was achieved with 10% OP on the sixth day of fermentation in batch SSF. Whereas, maximum PHB yield (4.19 g/L) was obtained within a shorter time (66 h)with OPH in the fed-batch experiment. The extracted PHB showed well-matched characteristic features to the standard PHB. Finally, this study proves the feasibility of employing the SSF process for PHB production using waste paper as an alternative approach to overcome the shortcoming of the separate hydrolysis and fermentation (SHF) process.

Kinetic study of ethanol production from different sizes of two-step pretreated oil palm trunk by fed-batch simultaneous saccharification and fermentation

Kinetic study of ethanol production from different sizes of two-step pretreated oil palm trunk by fed-batch simultaneous saccharification and fermentation

Life cycle assessment of bioethanol production from Pennisetum sp. using fed‐batch simultaneous saccharification and cofermentation at high solid loadings

Considerable progress has been achieved for the production of bioethanol from lignocellulosic biomass. However, increasing the substrate concentration has been shown to decrease ethanol productivity. Therefore, Saccharomyces cerevisiae (S. cerevisiae) and Pichia sp. were used for ethanol production from glucose and xylose sugars in the present investigation. Furthermore, coculture fermentations were conducted for 13 g/L of sugar (10 g of glucose and 3 g/L of xylose). It was further used for ethanol production from ultrasonication-assisted NaOH (UA-NaOH) pretreated and enzymatically saccharified biomass in batch and fed-batch fermentation conditions. Furthermore, fed-batch fermentation was used for separate hydrolysis and cofermentation (SHCF) and simultaneous saccharification and cofermentation (SSCF) in shake flask conditions. The highest ethanol production of 12.2 and 7.9 g/L was observed for fed-batch SSCF deenanath grass (DG) and hybrid Napier grass (HNG) (Palkonal MBW as the enzyme) biomass (80 g/L), respectively, in shake flask conditions. However, increasing the biomass concentration to 270 g/L produced an ethanol concentration of 77.6 and 51.3 g/L for DG and HNG, respectively, in fed-batch SSCF conditions in a bioreactor. Furthermore, nuclear magnetic resonance studies of the residual biomass of DG revealed lower carbohydrate content, demonstrating the efficiency of the fermentation strategy. Life cycle analysis of DG and HNG revealed DG had a higher yield as well as lower environmental impact than HNG. Thus, the fed-batch SSCF process can be considered a promising technique for biorefinery-based bioethanol production from Pennisetum sp. in the future. Novelty Statement For making lignocellulosic fuel ethanol economically competitive as compared to fossil fuels, it is important to achieve higher titers of ethanol from increased substrate concentration. But an increase in the substrate concentration decreases the ethanol productivity. In this study, the fed-batch simultaneous saccharification and fermentation produced higher titers of about 77.6 g/L ethanol even at higher substrate loadings. Besides, The LCA results demonstrated lower environmental toxicity, indicating the efficiency of the pretreatment and simultaneous saccharification and cofermentation process.

Cellulase Addition and Pre-hydrolysis Effect of High Solid Fed-Batch Simultaneous Saccharification and Ethanol Fermentation from a Combined Pretreated Oil Palm Trunk.

In the current study, alkaline hydrogen peroxide pretreated oil palm trunk fibers were subjected to ethanol production via simultaneous saccharification and fermentation (SSF). The effect of high substrate loading, enzyme and substrate feeding strategy, and influence of a pre-hydrolysis step in SSF was studied to scale up ethanol production. In the enzyme feeding strategy, the addition of an enzyme at the start of fed-batch SSF significantly (p < 0.05) increased ethanol concentration to 51.05 g/L, ethanol productivity (QP) to 0.61 g/L·h, and ethanol yield (YP/S) to 0.31 g/g, with a theoretical ethanol yield of 60.65%. Furthermore, the initial velocity of the enzyme (V0) in the first 8 h was 2.27 (g/h) with a glucose concentration of 18.17 g/L. On the other hand, the substrate feeding strategy and pre-hydrolysis simultaneous saccharification and fermentation (PSSF) process were studied in a 1 L fermenter. PSSF in fed batch with 10 and 20% (w/v) significantly improved enzyme hydrolysis, circumvent the problems of high viscosity, reduced overall fermentation time, and gave the highest ethanol concentration of 51.66 g/L, ethanol productivity (QP) of 0.72 g/L·h, ethanol yield (YP/S) of 0.31 g/g, and theoretical ethanol yield of 60.66%. In addition, PSSF with 10 and 20% significantly increased the initial velocity of the enzyme (V0) to 4.64 and 4.40 (g/h) and glucose concentration to 37.14 and 35.27 g/L, respectively. This result indicated that ethanol production by PSSF along with substrate feeding could enhance ethanol production efficiently.

Fed-batch simultaneous saccharification and fermentation including in-situ recovery for enhanced butanol production from rice straw

This paper describes a study of fed-batch SSFR (simultaneous saccharification, fermentation and recovery) for butanol production from alkaline-pretreated rice straw (RS) in a 2-L stirred tank reactor. The initial solid (9.2% w/v) and enzyme (19.9 FPU g-dw-1) loadings were previously optimized by 50-mL batch SSF assays. Maximum butanol concentration of 24.80 g L-1 was obtained after three biomass feedings that doubled the RS load (18.4% w/v). Butanol productivity (0.344 g L-1h−1) also increased two-fold in comparison with batch SSF without recovery (0.170 g L-1h−1). Although fed-batch SSFR was able to operate with a single initial enzyme dosage, an extra dosage of nutrients was required with the biomass additions to achieve this high productivity. The study showed that SSFR can efficiently improve butanol production from a lignocellulosic biomass accompanied by the efficient use of the enzyme.

High-Titer Lactic Acid Production by Pediococcus acidilactici PA204 from Corn Stover through Fed-Batch Simultaneous Saccharification and Fermentation.

Lignocellulose comprised of cellulose and hemicellulose is one of the most abundant renewable feedstocks. Lactic acid bacteria have the ability to ferment sugar derived from lignocellulose. In this study, Pediococcus acidilactici PA204 is a lactic acid bacterium with a high tolerance of temperature and high-efficiency utilization of xylose. We developed a fed-batch simultaneous saccharification and fermentation (SSF) process at 37 °C (pH 6.0) using the 30 FPU (filter paper units)/g cellulase and 20 g/L corn steep powder in a 5 L bioreactor to produce lactic acid (LA). The titer, yield, and productivity of LA produced from 12% (w/w) NaOH-pretreated and washed stover were 92.01 g/L, 0.77 g/g stover, and 1.28 g/L/h, respectively, and those from 15% NaOH-pretreated and washed stover were 104.11 g/L, 0.69 g/g stover, and 1.24 g/L/h, respectively. This study develops a feasible fed-batch SSF process for LA production from corn stover and provides a promising candidate strain for high-titer and -yield lignocellulose-derived LA production.

Improvement in Ethanol Yield from Lignocellulo-Starch Biomass using Saccharomyces cerevisiae alone or its Co-culture with Scheffersomyces stipitis

Background:Literature on ethanol production from Lignocellulo-Starch Biomass (LCSB) containing starch besides cellulose and hemicellulose, is scanty. Fed-Batch Separate Hydrolysis And Fermentation (F-SHF) was earlier found more beneficial than Fed-Batch Simultaneous Saccharification and Fermentation (F-SSF).Objective:The study aimed at modification of the saccharification and fermentation strategies by including a prehydrolysis step prior to the SSF and compared the ethanol yields with co-culture fermentation using hexose-fermenting Saccharomyces cerevisiae and pentose-fermenting Scheffersomyces stipitis.Methods:Fed-batch hybrid-SSF and Fed-Batch Separate Hydrolysis and Co-culture Fermentation (F-SHCF) in improving ethanol yield from Steam (ST) or Dilute Sulfuric Acid (DSA) pretreated LCSBs (peels of root and vegetable crops) were studied.Results:There was a progressive build-up of ethanol during F-HSSF up to 72h and further production up to 120h was negligible, with no difference among pretreatments. Despite very high ethanol production in the initial 24h of fermentation by S.cerevisiae under F-SHCF, the further increase was negligible. A rapid hike in ethanol production was observed when S. stipitis was also supplemented because of xylose conversion to ethanol.Conclusion:While ST gave higher ethanol (296-323 ml/kg) than DSA under F-HSSF, the latter was advantageous under F-SHCF for certain residues. Prehydrolysis (24h; 50°C) enhanced initial sugar levels favouring fast fermentation and subsequent saccharification and fermentation occurred concurrently at 37°C for 120h, thus leading to energy saving and hence F-HSSF was advantageous. Owing to the low hemicellulose content in LCSBs, the relative advantage of co-culture fermentation over monoculture fermentation was not significant.

Production of bioethanol from unwashed-pretreated rapeseed straw at high solid loading

Reduction in water consumption and increase in ethanol concentration are two main challenges for bioethanol production from lignocellulosic materials. To address the two challenges, the aim of this work was to study the production of bioethanol from unwashed-pretreated rapeseed straw (RS) at high solid loading. RS pretreated with 1% (w w−1) H2SO4 at 160 °C for 10 min resulted in excellent digestibility and fermentability of pretreated RS. The unwashed-pretreated RS was subjected to presaccharification and fed-batch simultaneous saccharification and fermentation (P-FB-SSF) at a final solid loading of 22% (w w−1). Ethanol concentration and ethanol yield of 53.1 g L−1 (equivalent to 4.1% (w w−1) based on fermentation slurry) and 72.4% were obtained, respectively. In total, 92.1 g water g−1 ethanol was consumed, a much smaller amount than that observed with washing after pretreatment or fermentation performed at lower solid loading.

Lactic acid production from pretreated corn stover with recycled streams

In order to overcome bottlenecks of the high amount of cellulase consumption in lignocellulosic l-Lactic acid (LA) production, a non-sterilized fed-batch simultaneous saccharification and fermentation (SSF) -membrane separation integration process was established in this current work. During the process, residual cellulase that remaining in the waste aqueous solution and solid residuals of corn stover (CS) were recycled and reused in subsequent fermentations. A total 6 rounds of operation were performed. Averagely, LA yield of 0.389 g g−1 (pretreated CS) was achieved, which was 1.20 times higher than that of the conventional process without waste stream recycling. Moreover, the wastewater discharge and the cost of nutrients for fermentation can also hugely decrease. Results indicated that cellulase, wastewater discharge and nutrients consumption of the process reduced by 47.4 %, 73.7 % and 86.1 %, respectively. This study opens a promising way for the reduction of second-generation LA production cost, which could significantly change the economic feasibility of the LA biorefineries.

L-lactic acid production by simultaneous saccharification and fermentation of dilute ethylediamine pre-treated rice straw

To effectively produce second-generation L-lactic acid (L-LA), for the first time, rice straw (RS) was pretreated by dilute ethylenediamine (EDA) and followed by fed-batch simultaneous saccharification and fermentation (SSF) under non-sterilized conditions. Specifically, the impact of pretreatment parameters included EDA concentration and pretreatment temperature on sugars and L-LA productions were evaluated. Results indicated that after pretreatment in 6% (w/v) EDA at 200 °C for 1 h and following the enzymatic hydrolysis, 42.25 g L−1 of total monomer sugars was generated. By batch SSF, the maximized 63.5 ± 3.0 g L−1and 296.8 g Kg−1 of L-LA can be obtained from the raw RS using Bacillus coagulans LA-15-2. Fed-batch SSF was further conducted and L-LA concentration of 92.5 g L−1 was obtained in the final fermentation broth. Correspondingly, L-LA productivity and yield reached 2.01 g L−1 h−1 and 578.1 g Kg−1of the pretreated RS, respectively. This study provided a novel environmental-friendly method for L-LA production, which successfully avoided the usage of large amount of inorganic alkali in lignocellulose pretreatment stage.

Improved Cellulosic Ethanol Titres from Highly Lignified Cotton Trash Residues Using Various Batch and Fed-Batch Process Configurations

This study investigates a fed-batch simultaneous saccharification fermentation (F-SSF) process to increase ethanol titres from highly lignified (41.6 wt.%) cotton gin trash residue. The optimal initial solid loading, enzyme dose, feed quantities and intervals to maximize substrate feed and subsequent ethanol titres were examined. Under batch SSF conditions, initial extracted cotton gin trash (ECGT) solid loadings were maximised at 19.35 wt.% and attained an ethanol titre of 23.3 g/l with a corresponding yield of 53.7%. Operating under optimised F-SSF mode, fermentations were initiated with 16.13 wt% EGCT solids followed by fresh ECGT feeds of 16.13 wt% and 12.9 wt.% at 12-h intervals. Cellulase levels were maintained at 44 FPU/g glucan throughout the fermentations. The final ethanol titre of 41 .4 g/l with a corresponding conversion rate of 70.1% was achieved after 72 h. Comparable ethanol yields of 40 g/l with 67.8% conversion were realized with lower cellulase dosing (25 FPU g/glucan) but only after extending the fermentation by 24 h.

Biodetoxification of Phenolic Inhibitors from Lignocellulose Pretreatment using Kurthia huakuii LAM0618T and Subsequent Lactic Acid Fermentation.

Phenolic inhibitors generated during alkaline pretreatment of lignocellulosic biomasses significantly hinder bacterial growth and subsequent biofuel and biochemical production. Water rinsing is an efficient method for removing these compounds. Nevertheless, this method often generates a great amount of wastewater, and leads to the loss of solid fiber particles and fermentable sugars. Kurthia huakuii LAM0618T, a recently identified microorganism, was herein shown to be able to efficiently transform phenolic compounds (syringaldehyde, hydroxybenzaldehyde, and vanillin) into less toxic acids. Taking advantage of these properties, a biodetoxification method was established by inoculating K. huakuii LAM0618T into the NH3/H2O2-pretreated unwashed corn stover to degrade phenolic inhibitors and weak acids generated during the pretreatment. Subsequently, 33.47 and 17.91 g/L lactic acid was produced by Bacillus coagulans LA204 at 50 °C through simultaneous saccharification and fermentation (SSF) from 8% (w/w) of NH3/H2O2-pretreated corn stover with or without K. huakuii LAM0618T-biodetoxification, indicating biodetoxification significantly increased lactic acid titer and yield. Importantly, using 15% (w/w) of the NH3/H2O2-pretreated K. huakuii LAM0618T-biodetoxified corn stover as a substrate through fed-batch simultaneous saccharification and fermentation, high titer and high yield of lactic acid (84.49 g/L and 0.56 g/g corn stover, respectively, with a productivity of 0.88 g/L/h) were produced by Bacillus coagulans LA204. Therefore, this study reported the first study on biodetoxification of alkaline-pretreated lignocellulosic material, and this biodetoxification method could replace water rinsing for removal of phenolic inhibitors and applied in biofuel and biochemical production using the alkaline-pretreated lignocellulosic bioresources.

A Combined Process for Production of Fumaric Acid and Xylooligosaccharides from Corncob

Production of fumaric acid and xylooligosaccharides from corncob was investigated using a combined process. Corncob was fractionated into a cellulose-rich fraction and a hemicellulose-rich fraction by an alkali pretreatment. The cellulose-rich fraction was converted into fumaric acid by Rhizopus oryzae in fed-batch simultaneous saccharification and fermentation (SSF). Maximal fumaric acid concentration reached 35.22 g/L at a final 15% (w/v) solid loading in the fed-batch SSF. The hemicellulose-rich fraction was converted into xylooligosaccharides (XOSs) by endo-β-1,4-xylanase. The yield of XOSs was 62.35% after 24 h of xylanase hydrolysis. Xylobiose, xylotriose, and xylotetraose were the three major components in the XOSs. A mass balance analysis demonstrated that 100.6 g of fumaric acid and 148.1 g of XOSs were produced from 1000 g of dry corncob matter. The production of fumaric acid and XOSs by the combined process could make the utilization of corncob more efficient and more promising.

The Integrated Process of Microbial Ensiling and Hot-Washing Pretreatment of Dry Corn Stover for Ethanol Production

In this study, we used dry corn stover (DCS) silage as feedstock to produce ethanol using hot-washing treatment (HWT) followed by prehydrolysis and fed-batch simultaneous saccharification and fermentation (FD-SSF) using cellulase and Saccharomyces cerevisiae. The inoculants product for ensiling of DCS was composed of lactic acid-producing organisms, such as Lactobacillus casei, Lactobacillus fermentum and Enterococcus durans. Moreover, the appropriate condition was selected by the dynamic analysis of silage quality. Among test conditions, the pH value (4.22), pretreatment time (4 week) and the content of lactic acid in DCS silage (4.32%) could be considered as important indicators of the success of microbial ensiling. The 16S rRNA gene-based pyrosequencing was used to analyze the community of the resulting silage, and the results indicated that Lactobacillus was the advantageous species. The observed glass transition temperature (Tg) value for DCS silage occurred at a temperature of 124.2 °C (Tmid). DCS silage was hydrothermally treated at temperature of Tg for 20 min. It was proved that biomass can be pretreated for cellulosic ethanol production by the integrated process of microbial ensiling and HWT. Ethanol fermentation of HWT-treated (at 30% glucan loading) DCS silage hydrolyzate (resulting in 61.92 g/L ethanol at 59.15% metabolic yield of FD-SSF) was reported in this work.

Sequential Targeting of Xylose and Glucose Conversion in Fed-Batch Simultaneous Saccharification and Co-fermentation of Steam-Pretreated Wheat Straw for Improved Xylose Conversion to Ethanol

Efficient conversion of both glucose and xylose in lignocellulosic biomass is necessary to make second-generation bioethanol from agricultural residues competitive with first-generation bioethanol and gasoline. Simultaneous saccharification and co-fermentation (SSCF) is a promising strategy for obtaining high ethanol yields. However, with this method, the xylose-fermenting capacity and viability of yeast tend to decline over time and restrict the xylose utilization. In this study, we examined the ethanol production from steam-pretreated wheat straw using an established SSCF strategy with substrate and enzyme feeding that was previously applied to steam-pretreated corn cobs. Based on our findings, we propose an alternative SSCF strategy to sustain the xylose-fermenting capacity and improve the ethanol yield. The xylose-rich hydrolyzate liquor was separated from the glucose-rich solids, and phases were co-fermented sequentially. By prefermentation of the hydrolyzate liquor followed fed-batch SSCF, xylose, and glucose conversion could be targeted in succession. Because the xylose-fermenting capacity declines over time, while glucose is still converted, it was advantageous to target xylose conversion upfront. With our strategy, an overall ethanol yield of 84% of the theoretical maximum based on both xylose and glucose was reached for a slurry with higher inhibitor concentrations, versus 92% for a slurry with lower inhibitor concentrations. Xylose utilization exceeded 90% after SSCF for both slurries. Sequential targeting of xylose and glucose conversion sustained xylose fermentation and improved xylose utilization and ethanol yield compared with fed-batch SSCF of whole slurry.

Optimization of simultaneous saccharification and fermentation conditions with amphipathic lignin derivatives for concentrated bioethanol production

Amphipathic lignin derivatives (A-LDs) prepared from the black liquor of soda pulping of Japanese cedar are strong accelerators for bioethanol production under a fed-batch simultaneous enzymatic saccharification and fermentation (SSF) process. To improve the bioethanol production concentration, conditions such as reaction temperature, stirring program, and A-LDs loadings were optimized in both small scale and large scale fed-batch SSF. The fed-batch SSF in the presence of 3.0g/L A-LDs at 38°C gave the maximum ethanol production and a high enzyme recovery rate. Furthermore, a jar-fermenter equipped with a powerful mechanical stirrer was designed for 1.5L-scale fed-batch SSF to achieve rigorous mixing during high substrate loading. Finally, the 1.5L fed-batch SSF with a substrate loading of 30% (w/v) produced a high ethanol concentration of 87.9g/L in the presence of A-LDs under optimized conditions.

Biological pretreatment of corn stover with Phlebia brevispora NRRL-13108 for enhanced enzymatic hydrolysis and efficient ethanol production.

Biological pretreatment of lignocellulosic biomass by white-rot fungus can represent a low-cost and eco-friendly alternative to harsh physical, chemical, or physico-chemical pretreatment methods to facilitate enzymatic hydrolysis. In this work, solid-state cultivation of corn stover with Phlebia brevispora NRRL-13018 was optimized with respect to duration, moisture content and inoculum size. Changes in composition of pretreated corn stover and its susceptibility to enzymatic hydrolysis were analyzed. About 84% moisture and 42 days incubation at 28°C were found to be optimal for pretreatment with respect to enzymatic saccharification. Inoculum size had little effect compared to moisture level. Ergosterol data shows continued growth of the fungus studied up to 57 days. No furfural and hydroxymethyl furfural were produced. The total sugar yield was 442 ± 5 mg/g of pretreated corn stover. About 36 ± 0.6 g ethanol was produced from 150 g pretreated stover per L by fed-batch simultaneous saccharification and fermentation (SSF) using mixed sugar utilizing ethanologenic recombinant Eschericia coli FBR5 strain. The ethanol yields were 32.0 ± 0.2 and 38.0 ± 0.2 g from 200 g pretreated corn stover per L by fed-batch SSF using Saccharomyces cerevisiae D5A and xylose utilizing recombinant S. cerevisiae YRH400 strain, respectively. This research demonstrates that P. brevispora NRRL-13018 has potential to be used for biological pretreatment of lignocellulosic biomass. This is the first report on the production of ethanol from P. brevispora pretreated corn stover. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:365-374, 2017.

Enhanced bioethanol production by fed-batch simultaneous saccharification and co-fermentation at high solid loading of Fenton reaction and sodium hydroxide sequentially pretreated sugarcane bagasse

A study on the fed-batch simultaneous saccharification and co-fermentation (SSCF) of Fenton reaction combined with NaOH pretreated sugarcane bagasse (SCB) at a high solid loading of 10–30% (w/v) was investigated. Enzyme feeding mode, substrate feeding mode and combination of both were compared with the batch mode under respective solid loadings. Ethanol concentrations of above 80g/L were obtained in batch and enzyme feeding modes at a solid loading of 30% (w/v). Enzyme feeding mode was found to increase ethanol productivity and reduce enzyme loading to a value of 1.23g/L/h and 9FPU/g substrate, respectively. The present study provides an economically feasible process for high concentration bioethanol production.