Fermentation Of Sugarcane Bagasse Research Articles

Optimization of Metal Ions in Sugarcane Bagasse Fermenting Medium for the Production of Streptokinase by Streptococcus equisimilis

Streptokinase is a fibrinolytic enzyme and a product of β-hemolytic Streptococci strains. This enzyme is used as a medication to break down clots in some cases of heart disease. Streptococcus equisimilis, a species of group C Streptococci, is widely used for the production of streptokinase by fermentation technology. In this study, the sugarcane bagasse fermentation medium was optimized for metal ions (KH2PO4, MgSO4.7H2O, CaCO3 and NaHCO3) at various levels to attain the maximal production of streptokinase. Sugarcane bagasse was used due to its profuse availability and as an ideal substrate for microbial processes for the manufacturing of value-added products. The results showed that maximal streptokinase production was found at 0.04% KH2PO4, 0.04% MgSO4.7H2O, 0.15% NaHCO3 and 0.04% CaCO3. Finally, the optimized medium resulted in 84.75 U/mg specific activity and 74.5% recovery. The purification process was carried out simultaneously using ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration. Finally, a purified sample of streptokinase was run on SDS-PAGE and resolute 47 kDa molecular weight. The use of β-hemolytic Streptococci to obtain streptokinase is not free from health risks and is related to anaphylaxis. This study provides a way forward for the cost-effective ways to obtain streptokinase for the treatment of thrombosis.

Optimization of Metal Ions in Sugarcane Bagasse Fermenting Medium for the Production of Streptokinase by Streptococcus equisimilis

Streptokinase is a fibrinolytic enzyme and a product of β-hemolytic Streptococci strains. This enzyme is used as a medication to break down clots in some cases of heart disease. Streptococcus equisimilis, a species of group C Streptococci, is widely used for the production of streptokinase by fermentation technology. In this study, the sugarcane bagasse fermentation medium was optimized for metal ions (KH2PO4, MgSO4.7H2O, CaCO3 and NaHCO3) at various levels to attain the maximal production of streptokinase. Sugarcane bagasse was used due to its profuse availability and as an ideal substrate for microbial processes for the manufacturing of value-added products. The results showed that maximal streptokinase production was found at 0.04% KH2PO4, 0.04% MgSO4.7H2O, 0.15% NaHCO3 and 0.04% CaCO3. Finally, the optimized medium resulted in 84.75 U/mg specific activity and 74.5% recovery. The purification process was carried out simultaneously using ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration. Finally, a purified sample of streptokinase was run on SDS-PAGE and resolute 47 kDa molecular weight. The use of β-hemolytic Streptococci to obtain streptokinase is not free from health risks and is related to anaphylaxis. This study provides a way forward for the cost-effective ways to obtain streptokinase for the treatment of thrombosis.

Vinasse from sugarcane bagasse (hemicellulose) acid hydrolysate and molasses supplemented: biodegradability and toxicity

Vinasse sugarcane is a valuable byproduct of the ethanol production process, presenting a perspective of volume increase with the development of second generation ethanol (2GE). However, this byproduct needs new methods of treatment and management for sustainability. Besides that, 2GE vinasse can be associated with some compounds (such as furan derivatives, phenolic compounds and organic acids), depending on the process used to solubilize hemicellulose, which could compromise vinasse destination or utilization. For this reason, detoxification methods of the hemicellulosic hydrolysates, from which vinasse is obtained in subsequent steps, are crucial. This study aimed to investigate whether the biological detoxification of vinasse from 2GE presents a difference concerning the microbial activity of biodegradation and toxicity when compared to vinasse without the detoxification process. Two vinasses (1, before; and 2, after detoxification) from fermented sugarcane bagasse (hemicellulose fraction) acid hydrolysate (supplemented with its molasses), under different concentrations: 2.5; 5 e 10% were evaluated. Their physicochemical characterization, biodegradation microbial activity (through Bartha and Pramer respirometric method, with total count of heterotrophic bacteria and fungi), and toxicity evaluation (through bioassays with Lactuca sativa at concentraction: 2.5; 5 e 10% and Daphnia similis to 1.5; 2.5; 3.5; 4.5; 5 and 10%) were performed. The results indicated high mineral and organic matter, which under a specific circumstance (2.5% of soil conditioning), enabled high efficiency in biodegradation (>80%). The bioassays with L. sativa signaled negative effect for radicular growth when the vinasses were applied at a concentration of 5 and 10% (sublethal effect and delayed root growth). Acute effects were observed in D. similis, with 50% of immobilization, at concentrations of 4.13% and 4.74% for vinasses 1 and 2, respectively. These results indicate that the biodegradation of vinasse from sugarcane bagasse acid hydrolysate occurs at relatively low levels (up to 5%) and suggests that higher concentrations (≥10%) may impair the growth of soil-associated microorganisms.

Effect of sugarcane bagasse as industrial by-products treated with Lactobacillus casei TH14, cellulase and molasses on feed utilization, ruminal ecology and milk production of mid-lactating Holstein Friesian cows.

The study aimed to evaluate the effect of Lactobacillus casei TH14, cellulase, and molasses combination fermented sugarcane bagasse (SB) as an exclusive roughage source in the total mixed ration (TMR) for mid-lactation 75% crossbred Holstein cows on feed intake, digestibility, ruminal ecology, milk yield and milk composition. Four multiparous mid-lactation crossbred (75% Holstein Friesian and 25% Thai native breed) dairy cows of 439 ± 16 kg body weight, 215 ± 5 days in milk and average milk yield 10 ± 2 kg d-1 were assigned to a 4× 4 Latin square design. The unfermented SB (SB-TMR), SB fermented with cellulase and molasses (CM-TMR), SB fermented with L. casei TH14 and molasses (LM-TMR), and SB fermented with L. casei TH14, cellulase and molasses (LCM-TMR) were used as dietary treatments. CM-TMR, LM-TMR and LCM-TMR significantly (P < 0.01) increased dry matter and fiber digestibility, gross energy and metabolizable energy intake (P < 0.05), blood glucose, total volatile fatty acids (P < 0.05), propionic acid and milk yield, but decreased ammonia, acetic acid, acetic:propionic ratio and methane production (P < 0.05) when compared with the SB-TMR. Compared with fermented SB treatments, LCM-TMR had lower (P < 0.05) ruminal ammonia and greater blood glucose (P < 0.01); LCM-TMR showed (P < 0.05) greater volatile fatty acids, propionic acid, milk yield and total solids, and lower acetic:propionic ratio (P < 0.01); methane, protozoa and somatic cell count were found to be lowest in LCM-TMR. Combination of L. casei TH14 and additives (LCM-TMR) effectively enhanced feed use, rumen ecology and milk production of Holstein Friesian cows. © 2021 Society of Chemical Industry.

Comparison of composting of chemically pretreated and fermented sugarcane bagasse for zero-waste biorefinery

Sugar industries produce vast quantity of sugarcane bagasse (SCB) waste which is used as raw material by biorefineries; however, the resulted pretreated waste or fermented residues remain unaddressed. Keeping sustainable utilization in view, recycling of pretreated SCB through composting was conducted for an eco-friendly waste management approach. This study was designed to recycle and evaluate biodegradation of different types of chemically pretreated and fermented SCB that were used as bulking agent under composting condition while untreated SCB set as control. After 112 days, composts were considered mature at 23–29 °C with pH 7.1–7.3 and 30–35% moisture content. Gravimetric analysis and FT-IR spectroscopy suggested that pretreated and untreated composted SCB showed significant cellulose reduction and delignification, respectively. Black gram seeds (Vigna mungo) were selected for phytotoxic test that showed germination index using compost extract > 80%, significantly higher than composted cattle manure and chemical fertilizer. Water holding capacity (WHC) of compost was highest in the case of fermented SCB suggesting the formation of better textured compost. Taken together, composting of chemically pretreated and fermented SCB resulted in improved biodegradation of lignocellulosic waste with better WHC and no phytotoxicity. The results may lead towards the establishment of a zero-waste sugarcane bagasse biorefinery.

In vitro Clot Lysis Activity of Phenolic Compound Degrading Product From Lignin Sugarcane Baggase Using Ochrobactrum sp.

Sugarcane bagasse (Saccharum officinarum L) is a readily available waste product of cane sugar processing. The content of lignocelluloses in sugarcane bagasse is approximately 52.7% cellulose, 20% hemicelluloses, and 24.2% lignin. Lignin can be degraded enzymatically by using microorganisms, such as Ochrobactrum sp. Monomer derived from lignin degradation using these bacteria in the optimum condition of sugarcane fermentation (pH 6, temperature 40 °C, for 5 days of incubation, the concentrations of starter 29%) by GC-MS yielded phenolic compounds such as 4-methyl-2, 6-di-tert-butylphenol; 2,6-di-tert-butylquinone; phenol, and p-hydroxybenzaldehide. The thrombolytic activity of these lignin monomers can be tested in-vitro by measuring the ability of clot lysis. Lignin did not have in-vitro clot lysis activity, whereas the lignin monomers in filtrat of fermented sugarcane bagasse have an in-vitro clot lysis activity, although its capacity is not as high as streptokinase.

One-step purification of two novel thermotolerant \u03b2-1,4-glucosidases from a newly isolated strain of Fusarium chlamydosporum HML278 and their characterization

A newly identified cellulase-producing Fusarium chlamydosporum HML278 was cultivated under solid-state fermentation of sugarcane bagasse, and two new β-glucosides enzymes (BG FH1, BG FH2) were recovered from fermentation solution by modified non-denaturing active gel electrophoresis and gel filtration chromatography. SDS-PAGE analysis showed that the molecular weight of BG FH1 and BG FH2 was 93 kDa and 52 kDa, respectively, and the enzyme activity was 5.6 U/mg and 11.5 U/mg, respectively. The optimal reaction temperature of the enzymes was 60 ℃, and the enzymes were stable with a temperature lower than 70 ℃. The optimal pH of the purified enzymes was 6.0, and the enzymes were stable between pH 4–10. Km and Vmax values ​​were 2.76 mg/mL and 20.6 U/mg for pNPG, respectively. Thin-layer chromatography and high-performance liquid chromatography analysis showed that BG FH1and BG FH2 had hydrolysis activity toward cellobiose and could hydrolyze cellobiose into glucose. In addition, both enzymes exhibited transglycoside activity, which could use glucose to synthesize cellobiose and cellotriose, and preferentially synthesize alcohol. In conclusion, our study demonstrated that F. chlamydosporum HML278 produces heat-resistant β-glucosidases with both hydrolytic activity and transglycosidic activity, and these β-glucosidases have potential application in bioethanol and papermaking industries.

Bioethanol Production from Sugarcane Bagasse Using &lt;em&gt;Neurospora intermedia &lt;/em&gt;in an Airlift Bioreactor

Bagasse as solid waste in sugarcane industry can be utilized as one of the potential raw materials in the bioprocess industry. This research aims to investigate the conversion of bagasse to bioethanol using simultaneous saccharification and fermentation in an airlift bioreactor. Neurospora intermedia was used as a biological agent that carried out the saccharification and fermentation of sugarcane bagasse simultaneously for bioethanol production. Cell morphology of N. intermedia in the form of pellet was required to provide free movement in the axial flow of airlift bioreactor. The medium pH strongly affects the morphological shape of N. intermedia. Therefore, the formation of good pellets of inoculum was observed under acidic conditions, i.e. pH 3.0 – 3.5. The effect of the initial concentration of nutrient on the inoculum growth was also investigated. Inoculums cultured in potato dextrose broth (PDB) medium with a half the strength of the common nutrient concentration of PDB qualitatively indicated good growth in terms of the size and density of cells. The inoculums with good morphological form were fed into the airlift bioreactor, which already contained a liquid medium with initial pH of 3.5 and also contained pre-treated bagasse. In experiments using the airlift bioreactor, the pre-treated bagasse was added to various nutrient concentrations of the PDB infusion medium. The highest bioethanol production from bagasse was monitored in the medium culture of half strength PDB infusion. The yield of bioethanol obtained from total sugarcane bagasse and PDB in an air lift bioreactor achieved approximately 40%, which has an infusion medium with a half-strength PDB and initial pH of 3.0.

Fermented sugarcane bagasse with Lactobacillus combined with cellulase and molasses promotes in vitro gas kinetics, degradability, and ruminal fermentation patterns compared to rice straw

This experiment was aimed to study the effect of sugarcane bagasse (SB) fermented with Lactobacillus casei TH14, cellulase, and molasses on in vitro gas kinetics, nutrient digestibility, and ruminal fermentation patterns compared to rice straw (RS). A 2 × 2 × 2 (+1) factorial arrangement in a completely randomized design was used. Factor A was levels of L. casei TH14 at 0 and 0.05 g/kg fresh matter, factor B was levels of cellulase at 0 and 104 U/kg fresh matter, and factor C was levels of molasses at 0 and 5 g of substrate DM. The (+1) treatment referred to RS fermentation without additives. The results showed that kinetics of gas, gas production, and total volatile fatty acid were not different between RS and SB treatment. RS had significantly (p < 0.05) greater nutrient digestibility, ruminal pH, ammonia-nitrogen, and protozoa compared the control SB. Compared with control RS and SB, SB fermented with additives had greater (p < 0.05) gas from soluble fraction and rate constant of gas, in vitro dry matter and neutral detergent fiber digestibility, and ruminal propionate. In conclusion, SB fermented with L. casei TH14, cellulase, and molasses in combination promoted ruminal gas production, in vitro digestibility, and ruminal fermentation patterns.

2-phenylethanol (rose aroma) production potential of an isolated pichia kudriavzevii through solid-state fermentation

2-phenylethanol (2-PE) is a higher alcohol widely used in industry that can be obtained by solid-state fermentation (SSF) using low-cost raw materials. This report describes the 2-PE production potential of an indigenous Pichia kudriavzevii isolated from solid-state fermented sugarcane bagasse that possesses attractive characteristics for processing waste streams such as its low-pH tolerance, high growth rate and temperature resistance. Besides, 2-PE production was optimized in batch-SSF using sugarcane bagasse supplemented with l-phenylalanine as substrate. Full factorial design allowed identifying the pH adjustment, micronutrient addition, inoculum and co-substrate load effects, and response surface methodology served to identify the maximum production based on temperature, initial moisture content (MC0) and specific airflow rate (SAFR). While the pH adjustment and micronutrient addition did not affect the 2-PE production, temperature and MC0 resulted critical for the process. After optimization, the maximum 2-PE content was 27.2 ± 0.2 mg per gram of dry substrate at 31 °C, 76 % MC0 and 0.129 L h−1 g−1 SAFR. This result was 23.8 % higher than the sub-optimal condition, and it is the highest 2-PE production via SSF reported so far. These results confirm the ability of P. kudriavzevii for producing 2-PE, and its potential for using waste streams as substrate.

Effect of feeding sugarcane bagasse treated with alkali and white rot fungi on dairy cow performance, blood metabolite and ruminal fermentation

Bagasse is the left over obtained from sugar production plants. After improving the quality with NaOH and white fungus, Pleurotus sajor-caju, it can be used as roughage source for ruminant animal. However, use at different levels in TMR diet is expected to produce different responses. Therefore, the objective this study is to find the suitable level of fermented sugarcane bagasse (FSB) as an ingredient in TMR with 14% dietary protein content on dairy cow performance, blood metabolite and ruminal fermentation. In CRD experiment, nine crossbred Holstein lactating multiparous cows (avg. b. wt. 405±45 kg) were randomly allotted to 3 dietary treatments comprising of 3 levels of FSB in TMR diet viz., 10, 20 and 30%. The result showed that inclusion of FSB at different levels in TMR diet had no effect on DMI and milk production. However, FSB at 20% in TMR had improved the milk composition. Increasing the level of FSB in TMR diet was effect to increase blood glucose, while blood urea nitrogen has the highest in 1.5 hours after feeding FSB at 10% in TMR diet. Level of FSB in TMR diet had no effect on ruminal fermentation as evidenced in every hour of determination, except 4.5 hours after feeding while FSB at 10 % in TMR diet had highest TVFA concentration in the rumen. Therefore, the study suggests that FSB at the level of 20-30% in TMR diet for optimum performance, blood metabolite and ruminal fermentation.

Co-fermentation of xylose and glucose from ionic liquid pretreated sugar cane bagasse for bioethanol production using engineered xylose assimilating yeast

An efficient method to co-ferment xylose and glucose in ionic liquid was developed via effective simultaneous saccharification and fermentation of sugar cane bagasse. Fermentation of pure xylose to ethanol in ionic liquids by two engineered xylose-assimilating Saccharomyces cerevisiae yeast strains, XR-XDH (Xylose Reductase-Xylitol Dehydrogenase pathway strain) and XI (Xylose isomerase pathway strain) resulted in lower conversion compared to ionic liquid-free medium. The ionic liquids however contributed to a higher saccharification efficiency of sugar cane bagasse. Among the five ionic liquids tested, 1-butyl-3-methylpyridinium chloride ([Bmpy][Cl]) yielded the highest saccharification efficiency resulting in 0.7 g/L xylose and 2.3 g/L glucose which are 5 and 2-folds, respectively, higher than the absence of ionic liquid. The high saccharification efficiency in [Bmpy][Cl] resulted in a more efficient assimilation of xylose from sugar cane bagasse in a simultaneous saccharification and fermentation process leading to 84.0% ethanol yield compared to 26.7% produced by the reference strain in the absence of ionic liquid. This efficient method for co-fermentation of xylose and glucose to ethanol will further enhance the effective utilization of biomass as a resource for bioethanol production.

Production, purification, characterization and application of a new halotolerant and thermostable endoglucanase of Botrytis ricini URM 5627

A halotolerant endoglucanase with a molecular mass of 39 kDa was obtained from the solid fermentation of sugarcane bagasse by the fungus Botrytis ricini URM 5627 and isolated using only two purification processes: fractionation with ammonium sulphate and size-exclusion chromatography resulting in an activity of 1289.83 U/mL. After the isolation, biochemical characterizations were performed, giving a temperature of 50 °C and optimum pH of 5. The enzyme was stable at 39–60 °C for 60 min and at a pH of 4–6. The enzymatic activity increased in the presence of Na+, Mn2+, Mg2+ and Zn2+ and decreased in the presence of Ca2+, Cu2+, and Fe2+. The endoglucanase revealed a halotolerant profile since its activity increased proportionally to an increase in NaCl concentration. The maximum activity was reached at 2 M NaCl with a 75% increase in activity. The enzyme had a Km of 0.1299 ± 0.0096 mg/mL and a Vmax of 0.097 ± 0.00121 mol/min/mL. During application in saccharification tests, the enzyme was able to hydrolyse sugarcane bagasse, rice husk, and wheat bran, with the highest production of reducers/fermentable sugars within 24 h of saccharification for wheat bran (137.21 mg/g). Therefore, these properties combined make this isolated enzyme a potential candidate for biotechnological and industrial applications.

Comparison of the biochemical properties between the xylanases of Thermomyces lanuginosus (Sigma®) and excreted by Penicillium roqueforti ATCC 10110 during the solid state fermentation of sugarcane bagasse

The biochemical properties of xylanase secreted by Penicilium roqueforti ATCC 10110 during the solid state fermentation of sugarcane bagasse were compared to xylanase by T. lanuginosus (Sigma®). The xylanase by P. roqueforti was maximized (19.95 IU.g−1) using the Box-Behnken experimental design and the optimized variables temperature, humidity and time. The addition of sucrose and glucose increased xylanase production. Biochemical properties related to time, pH, temperature, effect of ions and organic compounds and kinetic activity were studied and correlated for these two enzymes. Only xylanase by P. roqueforti was thermostable (50–80 °C) besides the activating effect in the presence of ions (Co+2, Ca+2, Na+1, Mg+2, Cu+2) among organic compounds only Trolox had an activating effect for both enzymes. Due to the degree of purity the values of Km and Vmax were distinct between the two enzymes. During 150 days xylanase activity remained above 95% if kept frozen. Xylanase by P. roqueforti extracted from the fermentation of sugarcane bagasse can be applied in food, beverage, pulp and paper processing.

Evaluation of a yeast co-culture for cellulase and xylanase production under solid state fermentation of sugarcane bagasse using multivariate approach

Sugarcane bagasse (SB), an abundantly found lignocellulosic material in many countries, has been exploited for the production of industrially important enzymes by filamentous fungi and bacteria. Yeasts have not been reported to utilize SB, particularly under solid-state fermentation (SSF). In this work, two yeast strains, MK-157 and MK-118 were co-cultured to produce a multienzyme preparation comprised of endoglucanase (EG), β-glucosidase (BGL) and xylanase (XYL). Two Plackett-Burman Designs (PBDs) were executed separately to screen the factors affecting SSF of acid-pretreated and alkali pretreated SB for the production of multienzyme. The analysis depicted that SSF of alkali pretreated SB yielded higher titers of multienzyme than acid pretreated SB and three of the factors (temperature, inoculum size and incubation period) were exerting significant effect on the process. Consequently, the three factors were optimized by employing Box-Behnken Design (BBD). Under optimum conditions, i.e. inoculation of 0.5 ml g−1 yeast co-culture in alkali pretreated SB and cultivation at 35 °C for 94 h gave the EG titers of 9.81 IU mL−1 that was comparable to the predicted value of 9.61 IU mL−1. Gravimetric analysis of untreated, pretreated and fermented SB showed that cultivation of the yeasts resulted in decrease in the quantity of cellulose, indicating utilization of this component. Moreover, alkaline pretreatment caused more delignification and disruption of the structure that was evident from scanning electron (SE) micrographs. SE microscopy also revealed that there were more changes in the structure of SB when cultivated with co-culture than with mono-culture. Furthermore, the fermented SB by co-culture adsorbed more dye (congo red) than the other SB indicating formation of pores in SB by the yeasts.

Enhancing the bioproduction of value-added aroma compounds via solid-state fermentation of sugarcane bagasse and sugar beet molasses: Operational strategies and scaling-up of the process

Bioproduction of generally recognized as safe (GRAS) products starting with low-cost raw materials has become significant in the biorefinery concept. Thus, the solid-state fermentation (SSF) of agro-industrial residues using GRAS strains appears as alternative to obtain aroma compounds. Here, the SSF of the mixture sugarcane bagasse/sugar beet molasses was used for producing a mixture of value-added fruit-like compounds. The study aimed to enhance the production and ester selectivity evaluating three operational strategies at three scales (0.5, 4.5 and 22 L) using non-sterilized residues. While the average total volatile production was 120 mgVol per gram of dry substrate (g−1ITS), fed-batch operation promoted the highest increases in the ester content up to 57 mgEst g−1ITS, an 88 and 59% more than in the static-batch and intermittent mixing modes respectively. Alternative operational strategies have compensated the scale-up adverse effects in the bioproduction, moving towards a sustainable large-scale application in a circular economy scheme.

Bioproduction of 2-phenylethanol and 2-phenethyl acetate by Kluyveromyces marxianus through the solid-state fermentation of sugarcane bagasse.

2-Phenylethanol (2-PE) and 2-phenethyl acetate (2-PEA) are important aroma compounds widely used in food and cosmetic industries due to their rose-like odor. Nowadays, due to the growing demand for natural products, the development of bioprocesses for obtaining value-added compounds has become of great significance. 2-PE and 2-PEA can be produced through the biotransformation of L-phenylalanine using the generally recognized as safe strain Kluyveromyces marxianus. L-phenylalanine bioconversion systems have been typically focused on submerged fermentation processes (SmF), but there is no information about other alternative productive approaches. Here, the solid-state fermentation (SSF) of sugarcane bagasse supplemented with L-phenylalanine was investigated as a sustainable alternative for producing 2-PE and 2-PEA in a residue-based system using Kluyveromyces marxianus as inoculum. An initial screening of the operational variables indicated that air supply, temperature, and initial moisture content significantly affect the product yield. Besides, it was found that the feeding strategy also affects the production and the efficiency of the process. While a basic batch system produced 16mgproducts per gram of residue (dry basis), by using split feeding strategies (fed-batch) of only sugarcane bagasse, a maximum of 18.4mgProductsg-1residue were achieved. Increase in product yield was also accompanied by an increase in the consumption efficiency of nutrients and precursor. The suggested system results as effective as other more complex SmF systems to obtain 2-PE and 2-PEA, showing the feasibility of SSF as an alternative for producing these compounds through the valorization of an agro-industrial residue.

Bioethanol from sugarcane bagasse: Focused on optimum of lignin content and reduction of enzyme addition

To investigate the effect of delignification on enzymatic saccharification and ethanol fermentation of sugarcane bagasse (SCB), NaClO, NaOH, and Na2CO3 were used to prepare SCB with different lignin contents. We found that a lignin content of approximately 11% was sufficient for enzymatic saccharification and fermentation. Based on this result, an economical delignification pretreatment method using a combination of acid and alkali (CAA) was applied. Lignin content of 11.7% was obtained after CAA pretreatment with 0.5% w/v H2SO4 at 140 °C for 10 min and 1.0% w/v NaOH at 90 °C for 60 min. Presaccharification-simultaneous saccharification and fermentation (P-SSF) of the CAA-pretreated SCB resulted in an ethanol concentration of 43.8 g/L and an ethanol yield of 81.7%, with an enzyme loading of 15 FPU/g–CAA-pretreated SCB. Enzyme activities (filter paper, carboxymethyl cellulase, and β-glucosidase activities) were determined in liquid phase during P-SSF, indicating that the residual cellulase activity could be further used. Thus, fed-batch P-SSF was carried out, and an ethanol concentration of 43.1 g/L and an ethanol yield of 80.4% were obtained with an enzyme loading of 10 FPU/g–CAA-pretreated SCB. Fed-batch P-SSF was found to be effective to reduce enzyme loading.

Utilization of agroindustrial residues for producing cellulases by Aspergillus fumigatus on Semi-Solid Fermentation

Agroindustrial biomasses (sugarcane bagasse, green coconut husk and cashew apple bagasse) are used as substrate for producing cellulases by Aspergillus fumigatus on Semi-Solid Fermentation (SSF). The untreated lignocellulosics and fermented sugarcane bagasse are characterized using the National Renewable Energy Laboratory (NREL) protocols analysis as well as through Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) assays. A two-variable central composite rotatable design (CCRD) coupled to response surface methodology (RSM) with three experiments at center point are used to investigate the influence of initial moisture and pH on carboxymethycellulose and filter paper, i.e., CMCase and FPase activities produced by the Aspergillus fumigatus using all of the three lignocellulosic biomasses. Results show that sugarcane bagasse has the highest cellulose content and the cashew apple bagasse the highest lignin content, approximately 46.0%. Additionally, pH and moisture (linear and quadratic parameters), as well as their combination, play a key role on both CMCase and FPase activities. The highest values for CMCase and FPase are 4.20 U/g and 0.64 U/g for sugarcane bagasse; 4.07 U/g and 0.28 U/g for coconut husk and 0.64 U/g and 0.32 U/g for cashew apple bagasse. The use of SSF for producing cellulases can be an option for reducing energy consumption due to reduction on the steps during biomass pretreatment.

Enhanced enzymatic hydrolysis and acetone-butanol-ethanol fermentation of sugarcane bagasse by combined diluted acid with oxidate ammonolysis pretreatment

This study aims to propose a biorefinery pretreatment technology for the bioconversion of sugarcane bagasse (SB) into biofuels and N-fertilizers. Performance of diluted acid (DA), aqueous ammonia (AA), oxidate ammonolysis (OA) and the combined DA with AA or OA were compared in SB pretreatment by enzymatic hydrolysis, structural characterization and acetone-butanol-ethanol (ABE) fermentation. Results indicated that DA-OA pretreatment improves the digestibility of SB by sufficiently hydrolyzing hemicellulose into fermentable monosaccharides and oxidating lignin into soluble N-fertilizer with high nitrogen content (11.25%) and low C/N ratio (3.39). The enzymatic hydrolysates from DA-OA pretreated SB mainly composed of glucose was more suitable for the production of ABE solvents than the enzymatic hydrolysates from OA pretreated SB containing high ratio of xylose. The fermentation of enzymatic hydrolysates from DA-OA pretreated SB produced 12.12g/L ABE in 120h. These results suggested that SB could be utilized efficient, economic, and environmental by DA-OA pretreatment.