Pretreated Sweet Sorghum Bagasse Research Articles

Assessing oxygen limiting fermentation conditions for 2,3-butanediol production from Paenibacillus polymyxa

2,3-butanediol (2,3-BDO) is a platform chemical that can be converted to a wide array of products ranging from bio-based materials to sustainable aviation fuel. This chemical can be produced by a variety of microorganisms in fermentation processes. Challenges remain for high titer 2,3-BDO production during fermentation due to several parameters, but controlling oxygen is one of the most relevant processing parameters to ensure viable product output. This work investigated the fermentation of plant biomass sugars by the 2,3-BDO producer Paenibacillus polymyxa. Aerobic and oxygen limited fermentation conditions were initially evaluated using molasses-based media to determine cell growth and 2,3-BDO output. Similar conditions were then evaluated on hydrolysate from pretreated sweet sorghum bagasse (SSB) that contained fermentable sugars from structural polysaccharides. Fermentations in molasses media under aerobic conditions found that 2,3-BDO could be generated, but over time the amount of 2,3-BDO decreased due to conversion back into acetoin. Oxygen limited fermentation conditions exhibited improved biomass growth, but only limited suppression of 2,3-BDO conversion to acetoin occurred. Glucose depletion appeared to have a greater role influencing 2,3-BDO conversion back into acetoin. Further improvements in 2,3-BDO yields were found by utilizing detoxified SSB hydrolysate.

Butyric Acid Generation by Clostridium tyrobutyricum from Low-Moisture Anhydrous Ammonia (LMAA) Pretreated Sweet Sorghum Bagasse.

Sweet sorghum bagasse (SSB) is an under-utilized feedstock for biochemical conversion to biofuels or high value chemicals. One such chemical that can be generated biochemically and applied to a wide array of industries from pharmaceuticals to the production of liquid transportation fuels is butyric acid. This work investigated cultivating the butyric acid producing strain Clostridium tyrobutyricum ATCC 25755 on low-moisture anhydrous ammonia (LMAA) pretreated SSB. Pretreated SSB hydrolysate was detoxified and supplemented with urea for shake flask batch fermentation to show that up to 11.4g/L butyric acid could be produced with a selectivity of 87% compared to other organic acids. Bioreactor fermentation with pH control showed high biomass growth, but a similar output of 11.3g/L butyric acid was achieved. However, the butyric acid productivity increased to 0.251g/L∙hr with a butyric acid yield of 0.29g/g sugar consumed. This butyric acid output represented an 83% theoretical yield. Further improvements in butyric acid titer and yield can be achieved by optimizing nutrient supplementation and incorporating fed-batch fermentation processing of pretreated SSB hydrolysate. Construction of ZGO:Sr NR- and ZGC@PDA NP-driven ratiometric aptasensor for CEA detection.

Enzymatic Hydrolysis Performance of Biomass by the Addition of a Lignin Based Biosurfactant

Hydrolysis of biomass for the production of fermentable sugar can be improved by the addition of surfactants. In pulp and paper mills, lignin, which is a by-product of the pulping process, can be utilized as a fine chemical. In the hydrolysis process, lignin is one of the major inhibitors of the enzymatic breakdown cellulose into sugar monomer. Therefore, the conversion of lignin into a biosurfactant offers the opportunity to solve the waste problem and improve hydrolysis efficiency. In this study, lignin derivatives, a biosurfactant, was applied to enzymatic hydrolysis of various lignocellulosic biomass. This Biosurfactant can be prepared by reacting lignin with a hydrophilic polymer such as polyethylene glycol diglycidylethers (PEDGE). In this study, the effect of biosurfactants on the enzymatic hydrolysis of pretreated sweet sorghum bagasse (SSB), oil palm empty fruit bunch, and sugarcane trash with different lignin contents was investigated. The results show that lignin derivatives improve the enzymatic hydrolysis of the pretreated biomass with low lignin content, however, it has less influence on the enzymatic hydrolysis of other pretreated biomass with lignin content higher than 10% (w/w). The use of biosurfactant on SSB kraft pulp can increase the sugar yield from 45.57% to 81.49%.

The Effects of Alkaline Pretreatment on Agricultural Biomasses (Corn Cob and Sweet Sorghum Bagasse) and Their Hydrolysis by a Termite-Derived Enzyme Cocktail

Sweet sorghum bagasse (SSB) and corncob (CC) have been identified as promising feedstocks for the production of second-generation biofuels and other value-added chemicals. In this study, lime (Ca(OH)2) and NaOH pretreatment efficacy for decreasing recalcitrance from SSB and CC was investigated, and subsequently, the pretreated biomass was subjected to the hydrolytic action of an in-house formulated holocellulolytic enzyme cocktail (HEC-H). Compositional analysis revealed that SSB contained 29.34% lignin, 17.75% cellulose and 16.28% hemicellulose, while CC consisted of 22.51% lignin, 23.58% cellulose and 33.34% hemicellulose. Alkaline pretreatment was more effective in pretreating CC biomass compared to the SSB biomass. Both Ca(OH)2 and NaOH pretreatment removed lignin from the CC biomass, while only NaOH removed lignin from the SSB biomass. Biomass compositional analysis revealed that these agricultural feedstocks differed in their chemical composition because the CC biomass contained mainly hemicellulose (33–35%), while SSB biomass consisted mainly of cellulose (17–24%). The alkaline pretreated SSB and CC samples were subjected to the hydrolytic action of the holocellulolytic enzyme cocktail, formulated with termite derived multifunctional enzymes (referred to as MFE-5E, MFE-5H and MFE-45) and exoglucanase (Exg-D). The HEC-H hydrolysed NaOH pretreated SSB and CC more effectively than Ca(OH)2 pretreated feedstocks, revealing that NaOH was a more effective pretreatment. In conclusion, the HEC-H cocktail efficiently hydrolysed alkaline pretreated agricultural feedstocks, particularly those which are hemicellulose- and amorphous cellulose-rich, such as CC, making it attractive for use in the bioconversion process in the biorefinery industry.

Integrated processes for production of cellulosic and hemicellulosic biobutanol from sweet sorghum bagasse using autohydrolysis

Different process alternatives were assessed for production of hemicellulosic and cellulosic butanol from sweet sorghum bagasse (SSB) based on integration of autohydrolysis, enzymatic hydrolysis, and ABE fermentation. The liquor obtained through single or two-stage autohydrolysis was subjected to post-hydrolysis using a commercial hemicellulases blend and fermentation by Clostridium acetobutylicum. The pretreated solids obtained at each stage of autohydrolysis were also used for ABE production through separated hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF) using a commercial cellulase blend. The two-stage autohydrolysis (at 150 °C for 30 min; 120 °C for 60 min) followed by enzymatic post-hydrolysis resulted in 6.6 g/L sugar and fermented to 4.6 g/L ABE. On the other hand, enzymatic hydrolysis and ABE fermentation of the pretreated SSB led to 4.7–5.4 g/L ABE. In this process, 32 g hemicellulosic and 85 g cellulosic ABE were produced from each kg SSB. Besides, other thirteen process alternatives were compared based on the overall yield of ABE production from SSB. In the most compact process, the four enzymatic hydrolysis and fermentation stages were combined into a single stage named “simultaneous co-saccharification and fermentation (SCSF)" leading to 21−22 g ABE/kg SSB.

Pretreatment of Sweet Sorghum Bagasse for Ethanol Production Using Na2CO3 Obtained by NaOH Absorption of CO2 Generated in Sweet Sorghum Juice Ethanol Fermentation

(1) Background: Commercial production of fuel ethanol currently uses sugarcane and corn as feedstocks. Attempts to develop other renewable feedstocks that are more abundant have led to lignocellulosic biomass, which requires pretreatment prior to enzymatic hydrolysis to generate fermentable sugars. One of the largest cost components of pretreatment is chemical cost. Ethanol fermentation also produces large quantities of CO2 as a co-product contributing to global warming. (2) Methods: Sweet sorghum has emerged as a potential new feedstock for ethanol production. In the present study, the CO2 produced in sweet sorghum juice (SSJ) fermentation was captured by absorption in 5 M NaOH. The resultant Na2CO3 solution was used for pretreatment of sweet sorghum bagasse (SSB), which is the solid residue in SSJ extraction. The pretreated SSB was fermented in SSJ to produce additional ethanol. (3) Results: CO2 absorption efficiency of 92.0% was observed. Pretreatment of SSB by the obtained Na2CO3 solution resulted in no loss of glucan and only 8.1 wt% loss of xylan. Ethanol yield from glucan in the pretreated SSB was 81.7% theoretical. (4) Conclusions: CO2 from SSJ fermentation captured as Na2CO3 could be used for efficient SSB pretreatment. Further study focusing on pretreatment process optimization is needed.

A comparison of methods of ethanol production from sweet sorghum bagasse

Ethanol production from sweet sorghum bagasse (SSB) is reported. A two-step pretreatment with hydrogen peroxide followed by NaOH at 121 °C for 20 min, was used prior to enzymatic treatment. Enzymatic treatment was carried out using a commercial cellulase. Enzymatic hydrolysis for 72 h resulted in a hydrolysate containing xylose (5.1 g L−1), glucose (75.3 g L−1) and cellobiose (1.4 g L−1). This hydrolysate was used to produce ethanol by a 72-h fermentation with the yeast Saccharomyces cerevisiae TISTR 5606 at 30 °C. This separate hydrolysis and fermentation (SHF) method was compared with a simultaneous saccharification and fermentation (SSF) method. The SSF process used the pretreated SSB and was carried out in two different ways: (1) In the first method, the enzyme, the substrate and the yeast inoculum were mixed and SSF fermentation took place at 37 °C for 72-h, to produce a final ethanol concentration of 22.3 g L−1; (2) in the second method, termed the ‘delayed simultaneous-saccharification fermentation’ or DSSF, the pretreated SSB was enzymatically hydrolyzed at 50 °C for 6-h, cooled to 37 °C, and then inoculated with the yeast to commence a 66-h fermentation. This gave a final ethanol concentration of 28.3 g L−1. The ethanol productivity was 0.31 g L−1 h−1 for the SHF and SSF processes, but the DSSF had a ∼26% higher productivity.

Biochemical conversion of sweet sorghum bagasse to succinic acid

Succinic acid, an important intermediate in the manufacture of plastics and other commodity and specialty chemicals, is currently made primarily from petroleum. We attempted to biosynthesize succinic acid through microbial fermentation of cellulosic sugars derived from the bagasse of sweet sorghum, a renewable feedstock that can grow in a wide range of climates around the world. We investigated pretreating sweet sorghum bagasse (SSB) with concentrated phosphoric acid at mild conditions (40-85°C) at various residence times and biomass concentrations. We then subjected the pretreated SSB to enzymatic hydrolysis with a commercial cellulase to release glucose. The highest glucose yield was obtained when SSB was pretreated at 50°C for 43minat 130g/L biomass concentration on dry basis. Fermentation was carried out with Actinobacillus succinogenes 130Z, which readily converted 29.2g/L of cellulosic glucose to 17.8g/L of succinic acid in a 3.5-L bioreactor sparged with CO2 at a rate of 0.5vvm, thus reducing the carbon footprint of the process. Overall, we demonstrated, for the first time, the use of SSB for production of succinic acid using practices that lower energy use, future equipment cost, waste generation, and carbon footprint.

A subcritical pretreatment improved by self-produced organic acids to increase xylose yield

Pretreatment is a crucial step to utilize biomass in the cellulosic ethanol industry, high xylose yield and green pretreatment methods are of concern recently. This study used the self-produced organic acids present in the pretreated liquid to enhance the hydrothermal pretreatment of sweet sorghum bagasse. By comparing pretreatments with acetic acid, lactic acid and self-produced organic acids, it was found that the self-produced organic acids could effectively promote the formation of xylose and inhibit its degradation to furfural. The pretreatments with lactic-acetic acid confirmed that the copresence of acetic acid and lactic acid contributed to the promotion of pretreatment during using self-produced organic acids. The suitable ratio of lactic to acetic was 6:4. Through multi-factor optimization experiments, the suitable conditions were determined as 178–182 °C for 40–45 min with 1.00–1.10 wt% self-produced organics, and the xylose yield was 83–85%. The effect of reused times of pretreated liquid was explored. The results showed that the number of reuse process should not exceed two, otherwise the accumulated by-products may affect the subsequent fermentation. The proposed method could reduce the consumption of water and organic acids, indicating its potentiality in cleaner utilization of biomass.

Microwave and steam mediated alkaline pretreatments of sweet sorghum bagasse: Study of the energy efficiency

The effects of microwave and steam mediated pretreatments were evaluated and compared relative to the hydrolysis of sweet sorghum bagasse (SSB) in the presence of sodium hydroxide. The results established the optimum parameters for energy consumption and sugar production after hydrolysis of the pretreated SSB. The energy balance was better in microwave treatment compared with the steam treatment. The results recommended pretreatment at 300 watts power setting in the microwave oven up to 10 min. At higher wattage setting and longer exposure time, increased sugar yields were obtained, although the efficiency of the process decreased when the energy balance was calculated. The energy balance was calculated as the proportion of energy consumed during the pretreatments to the energy that can be produced by fermenting released glucose to ethanol. In this study, the energy consumed during the different pretreatments varied from 1/33 to 1/200 of the energy obtainable by fermenting released glucose to ethanol. Overall, the pretreatment of SSB to produce fermentable sugars was effective, and the energy balance was positive both in microwave and steam pretreatments of alkaline suspension of SSB. In microwave treatment the energy applied can be more accurately dosed, and consequently the energy balance was improved compared to steam treatment.

Effects of hydrochloric acid washing on the microstructure and pyrolysis bio-oil components of sweet sorghum bagasse

Acid washing is an alternative and promising approach for biomass to produce high-quality bio-oil. The hydrochloric acid washing pretreatment of sweet sorghum bagasse was performed in this study. The effects of acid washing on the ultrastructure of sweet sorghum bagasse were investigated using scanning electron microscope and Fourier transform infrared, and the effects on pyrolysis using thermogravimetric analyzer and a fast pyrolysis device. The results indicated acid treatment obviously changed the surface morphology of the cell walls of sweet sorghum bagasse, effectively removed most metals from sweet sorghum bagasse, and increased the volatiles and bio-oil yields. The results showed that bio-oil produced from pretreated sweet sorghum bagasse contained less components categories, lower contents of phenols, aldehydes, furans and alcohols, while much higher contents of d-allose and ketones than that from the original sample. Hydrochloric acid-washing pretreatment of sweet sorghum bagasse can increase the contents of some high-value chemicals in bio-oil.

Simultaneous saccharification and juice co-fermentation for high-titer ethanol production using sweet sorghum stalk

The acid pretreated sweet sorghum bagasse was mixed with the fermentable juice for ethanol production by simultaneous saccharification and juice co-fermentation (SSJcF). The effect of sulfuric acid concentration on ethanol production was evaluated. Two-phase of fermentation was occurred distinctly during the process. Under the optimized conditions (2% of sulfuric acid and 20 FPU/g of cellulase added at 0 h), 120.41 ± 0.4 g/L of ethanol was achieved after 216 h of inoculation, with ethanol yield of 67.75 g/kg of the fresh sweet sorghum stalk (FSSS) that contained water and was rich in monosaccharide and cellulosic biomass. This study provided a potential way for high titer ethanol production by SSJcF using FFFS, which is benefited to the downstream ethanol separation processes.

Evaluation of six ionic liquids and application in pretreatment of sweet sorghum bagasse for bacterial nanocellulose production

AbstractBACKGROUNDBacterial nanocellulose (BNC) is a versatile biomaterial, however its production at industrial scale is not cost‐effective due to the high cost of culture media. Sweet sorghum bagasse (SSB) is an annually renewable agricultural residue with little or no value and could even cause haze if burned. The proposed approach is the first to use SSB to produce BNC by means of pretreatment of green solvent ionic liquid (IL) for promoted enzymatic saccharification due to the recalcitrant lignocellulose structure of SSB. But the questions, ‘Which is the best IL’ and ‘Are there any negative effects’ need answers.RESULTSSix kinds of ILs were first compared in detail and showed diverse inhibition of cellulase and bacterial culture with changing IL concentration. Inhibition by IL of cellulase and BNC production could be removed completely by thorough washing. The results showed that three ILs, [AMIM]OAc, [EMIM]Fmt and [EMIM]OAc, had higher dissolving capacity and strong enhancement of cellulase saccharification of SSB. The fermentable sugar yield from SSB was enhanced by more than 7.5 times after [EMIM]Fmt‐pretreatment at biomass loading of 20%. The highest productivity of 0.71 g L−1 d−1 of crude BNC was obtained after cultivation with the hydrolysate of [EMIM]Fmt‐pretreated SSB.CONCLUSIONThe results demonstrated a new approach to produce BNC by biorefining lignocellulosic waste SSB, which could provide the following potential benefits: better utilization of the agricultural residual SSB than burning, which causes haze and air pollution, improving economic benefits of SSB for farmers, and decreasing the production cost of BNC. © 2018 Society of Chemical Industry

Near theoretical saccharification of sweet sorghum bagasse using simulated green liquor pretreatment and enzymatic hydrolysis

Sweet sorghum is a tropical grass that can tolerate harsh conditions and has great potential as a feedstock for biofuel production. The green liquor, which is an intermediate liquid stream containing Na2CO3, Na2S and other impurities generated in a kraft pulp mill, has been shown to remove lignin and preserve carbohydrates during pretreatment. The recoveries of key components and reconstitution of green liquor have also been demonstrated in kraft pulp mills. In this study, the potential use of a simulated green liquor (SGL), which contained only Na2CO3 and Na2S, for pretreatment of sweet sorghum bagasse to improve its enzymatic hydrolysis to produce sugars for use in further bioconversion to biofuel was investigated. To study the effects of key process parameters (time, temperature, liquid/solid (L/S) ratios, total titratable alkali (TTA) charges, and sulfidity), the SGL pretreatment was optimized by using response surface methodology. The optimum pretreatment conditions for the highest total sugar yield were determined to be 110 min, 160 °C, L/S ratio of 7, TTA of 18%, and sulfidity of 40%. The optimal total sugar yield predicted by the model was 83.2%. The predicted value was confirmed in an experiment where the overall sugar yield of 82.6% was obtained.

Techno-Economic Evaluation of Cellulosic Ethanol Production Based on Pilot Biorefinery Data: a Case Study of Sweet Sorghum Bagasse Processed via L+SScF

Replacing fossil fuels with renewable fuels derived from lignocellulosic biomass can contribute to the mitigation of global warming and the economic development of rural communities. This will require lignocellulosic biofuels to become price competitive with fossil fuels. Techno-economic analyses can provide insights into which parts of the biofuel production process need to be optimized to reduce cost or energy use. We used data obtained from a pilot biorefinery to model a commercial-scale biorefinery that processes lignocellulosic biomass to ethanol, with a focus on the minimum ethanol selling price (MESP). The process utilizes a phosphoric acid-catalyzed pre-treatment of sweet sorghum bagasse followed by liquefaction and simultaneous saccharification and co-fermentation (L+SScF) of hexose and pentose sugars by an engineered Escherichia coli strain. After validating a techno-economic model developed with the SuperPro Designer software for the conversion of sugarcane bagasse to ethanol by comparing it to a published Aspen Plus model, six different scenarios were modeled for sweet sorghum bagasse Under the most optimistic scenario, the ethanol can be produced at a cost close to the energy-equivalent price of gasoline. Aside from an increase in the price of gasoline, the gap between ethanol and gasoline prices could also be bridged by either a decrease in the cost of cellulolytic enzymes or development of value-added products from lignin.

Sweet Sorghum Bagasse Pretreatment by Coriolus versicolor in Mesh Tray Bioreactor for Selective Delignification and Improved Saccharification

Fungal pretreatment of sweet sorghum bagasse (SSB) by solid state fermentation (SSF) studied in a Mesh tray bioreactor. In pretreatment by using Coriolus versicolor, optimal mesh size in tray and humid airflow into bioreactor overcame the problems of SSF and improved fungal growth; increased the production of lignolytic enzymes laccase, lignin peroxidase, manganese peroxidase, polyphenol peroxidase, aryl alcohol oxidase by 1.9, 1.85, 2.6, 2.0, 1.9 folds respectively; hemicellulolytic enzyme xylanase by 1.8 folds and decreased cellulolytic enzymes production. Altered lignocellulolytic enzyme profiles resulted in high lignin degradation 46.09 ± 2.0% w w−1, high selectivity value 5.98 and low cellulose loss 7.7 ± 0.3% w w−1. Enzymatic hydrolysis of pretreated SSB yielded higher (~ 2.47 times) fermentable sugar. Characterizations of SSB by SEM, XRD, FTIR, TGA/DTG supported the results. Mesh tray bioreactor could be used for fungal pretreatment and enzyme productions by SSF of waste biomass.

Biological and Physicochemical Pretreatment of Sweet Sorghum Bagasse to Liberate Reducing Sugars

Biological and Physicochemical Pretreatment of Sweet Sorghum Bagasse to Liberate Reducing Sugars

THE EFFECTIVENESS OF PHYSICAL AND ALKALI HYDROTHERMAL PRETREATMENT <br> IN IMPROVING ENZYME SUSCEPTIBILITY OF SWEET SORGHUM BAGASSE

Sweet sorghum bagasse (SSB) obtained after juice extraction is a potential feedstock for fermentable sugars production that can be further fermented to different kinds of products, such as ethanol or lactic acid. The proper particle size resulted from phsyical pretreatment and different pretreatment processes including water, alkali, hydrothermal, and alkali hydrothermal for improving enzyme susceptibility of SSB have been investigated. After grinding to particle sizes of <250 ?m, 250-420 ?m, and, > 420 ?m the sweet sorghum bagasse was washed to eliminate residual soluble sugars present in the bagasse. Dosages of cellulase enzyme used in saccharification were 60 and 100 FPU/g substrate, respectively. The results showed that SSB with particle sizes of 250-420 ?m had the highest cellulose (38.33%) and hemicellulose content (31.80%). Although the yield of reducing sugar of 250-420 ?m size particles was lower than that of smaller particle (<250 ?m), the former was more economical in the energy consumption for milling process. The yields of reducing sugar obtained from enzymatic hydrolysis of alkali hydrothermal pretreated sweet sorghum bagasse were 1.5 and 0.5 times higher than that from untreated sweet sorghum bagasse at enzyme loading of 100 and 60 FPU/g substrate, respectively. Furthermore, alkali hydrothermal pretreatment was able to remove as much as 85% of lignin. Morphological analysis using SEM (Scanning Electron Microscope) showed that samples treated with alkali hydrothermal have more pores and distorted bundles than that of untreated sweet sorghum bagasse. Meanwhile, XRD (X-ray diffraction) analysis showed that pretreated samples had a higher crystallinity and smaller crystallite size than untreated sweet sorghum bagasse, which might be due to removal of amorphous lignin components.

Ethanol production from sweet sorghum bagasse through process optimization using response surface methodology.

In this study, comparative evaluation of acid- and alkali pretreatment of sweet sorghum bagasse (SSB) was carried out for sugar production after enzymatic hydrolysis. Results indicated that enzymatic hydrolysis of alkali-pretreated SSB resulted in higher production of glucose, xylose and arabinose, compared to the other alkali concentrations and also acid-pretreated biomass. Response Surface Methodology (RSM) was, therefore, used to optimize parameters, such as alkali concentration, temperature and time of pretreatment prior to enzymatic hydrolysis to maximize the production of sugars. The independent variables used during RSM included alkali concentration (1.5-4%), pretreatment temperature (125-140°C) and pretreatment time (10-30min) were investigated. Process optimization resulted in glucose and xylose concentration of 57.24 and 10.14g/L, respectively. Subsequently, second stage optimization was conducted using RSM for optimizing parameters for enzymatic hydrolysis, which included substrate concentration (10-15%), incubation time (24-60h), incubation temperature (40-60°C) and Celluclast concentration (10-20IU/g-dwt). Substrate concentration 15%, (w/v) temperature of 60°C, Celluclast concentration of 20IU/g-dwt and incubation time of 58h led to a glucose concentration of 68.58g/l. Finally, simultaneous saccharification fermentation (SSF) as well as separated hydrolysis and fermentation (SHF) was evaluated using Pichia kudriavzevii HOP-1 for production of ethanol. Significant difference in ethanol concentration was not found using either SSF or SHF; however, ethanol productivity was higher in case of SSF, compared to SHF. This study has established a platform for conducting scale-up studies using the optimized process parameters.

Fungal pretreatment of sweet sorghum bagasse with supplements: improvement in lignin degradation, selectivity and enzymatic saccharification

Sweet sorghum bagasse (SSB) from food processing and agricultural industry has attracted the attention for uses in production of biofuel, enzymes and other products. The alteration in lignocellulolytic enzymes by use of supplements in fungal pretreatment of SSB to achieve higher lignin degradation, selectivity value and enzymatic hydrolysis to fermentable sugar was studied. Fungal strain Coriolus versicolor was selected for pretreatment due to high ligninolytic and low cellulolytic enzyme production resulting in high lignin degradation and selectivity value. SSB was pretreated with supplements of veratryl alcohol, syringic acid, catechol, gallic acid, vanillin, guaiacol, CuSO4 and MnSO4. The best results were obtained with CuSO4, gallic acid and syringic acid supplements. CuSO4 increased the activities of laccase (4.9-fold) and polyphenol oxidase (1.9-fold); gallic acid increased laccase (3.5-fold) and manganese peroxidase (2.5-fold); and syringic acid increased laccase (5.6-fold), lignin peroxidase (13-fold) and arylalcohol oxidase (2.8-fold) resulting in enhanced lignin degradations and selectivity values than the control. Reduced cellulolytic enzyme activities resulted in high cellulose recovery. Enzymatic hydrolysis of pretreated SSB yielded higher sugar due to degradation of lignin and reduced the crystallinity of cellulose. The study showed that supplements could be used to improve the pretreatment process. The results were confirmed by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric/differential thermogravimetric analysis of SSB.