1
|
Biswas B, Biswas AB. Effects of some chemical nutrients on bio-ethanol production from water hyacinth (Eichhornia crassipes) hydrolyzed by heat and ethanol resistant strain of Saccharomyces cerevisiaeAB810. J INDIAN CHEM SOC 2022. [DOI: 10.1016/j.jics.2022.100725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
2
|
Guo Y, Liu G, Ning Y, Li X, Hu S, Zhao J, Qu Y. Production of cellulosic ethanol and value-added products from corn fiber. BIORESOUR BIOPROCESS 2022; 9:81. [PMID: 38647596 PMCID: PMC10991675 DOI: 10.1186/s40643-022-00573-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 08/03/2022] [Indexed: 11/10/2022] Open
Abstract
Corn fiber, a by-product from the corn processing industry, mainly composed of residual starch, cellulose, and hemicelluloses, is a promising raw material for producing cellulosic ethanol and value-added products due to its abundant reserves and low costs of collection and transportation. Now, several technologies for the production of cellulosic ethanol from corn fiber have been reported, such as the D3MAX process, Cellerate™ process, etc., and part of the technologies have also been used in industrial production in the United States. The ethanol yields range from 64 to 91% of the theoretical maximum, depending on different production processes. Because of the multicomponent of corn fiber and the complex structures highly substituted by a variety of side chains in hemicelluloses of corn fiber, however, there are many challenges in cellulosic ethanol production from corn fiber, such as the low conversion of hemicelluloses to fermentable sugars in enzymatic hydrolysis, high production of inhibitors during pretreatment, etc. Some technologies, including an effective pretreatment process for minimizing inhibitors production and maximizing fermentable sugars recovery, production of enzyme preparations with suitable protein compositions, and the engineering of microorganisms capable of fermenting hexose and pentose in hydrolysates and inhibitors tolerance, etc., need to be further developed. The process integration of cellulosic ethanol and value-added products also needs to be developed to improve the economic benefits of the whole process. This review summarizes the status and progresses of cellulosic ethanol production and potential value-added products from corn fiber and presents some challenges in this field at present.
Collapse
Affiliation(s)
- Yingjie Guo
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
| | - Yanchun Ning
- Research Institute of Jilin Petrochemical Company, PetroChina, No. 27, Zunyidong Road, Jilin City, 132021, Jilin, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China.
| | - Shiyang Hu
- Research Institute of Jilin Petrochemical Company, PetroChina, No. 27, Zunyidong Road, Jilin City, 132021, Jilin, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China.
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao, 266237, Shandong, China
| |
Collapse
|
3
|
Water Hyacinth: A sustainable cellulose source for cellulose nanofiber production and application as recycled paper reinforcement. JOURNAL OF POLYMER RESEARCH 2022. [DOI: 10.1007/s10965-022-03089-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
4
|
Ganorkar PV, Jadeja GC, Desai MA. Extraction of shikimic acid and recovery of lignocelluloses from water hyacinth. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02249-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
5
|
El‐Wakil AE, Abd‐Elbasseer M, M.El‐Basheer T. Mechanical and acoustical properties of Eichhornia crassipes (water hyacinth) fiber‐reinforced styrene butadiene rubber. POLYMER COMPOSITES 2021; 42:3732-3745. [DOI: 10.1002/pc.26088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 04/13/2021] [Indexed: 09/01/2023]
Abstract
AbstractThe essential target of this investigation is to valorize an Eichhornia crassipes fiber (ECF) and maleates of Eichhornia crassipes fiber (MoECF) as reinforcing fillers in styrene‐butadiene rubber (SBR) composites in terms of the mechanical, acoustical, thermal, and morphological properties. Fourier transforms infrared spectroscopy characterizes the esterification of ECF with maleic anhydride (MA) and the graft of MoECF onto SBR. SBR composites manufactured with different loadings of ECF and MoECF (1, 2.5, 5, 10, and 20 phr). Scanning electron microscope illustrates the MoECF upgrade interfacial adhesion with the SBR matrix. It is observed that 5 and 20 phr of MoECF enhance the tensile strength and elongation at break of SBR composites by 8% and 310%, respectively. 10 phr of MoECF maintains the tensile strength of SBR composite during the accelerated thermal aging course. While 20 phr of MoECF improves the tensile strength of SBR composite by 19% with increment‐accelerated thermal aging time to 7 days. The higher loading (10 and 20 phr) of MoECF ameliorates the thermal stability of SBR composites. SBR composite containing 10 phr of MoECF has sound absorption amplitude equal to 0.9 at the frequency of 400 Hz. The sound absorption performance improved within low‐frequency regions below 500 Hz with increasing thickness to 2.3 mm.
Collapse
Affiliation(s)
- Abd El‐Aziz El‐Wakil
- Polymer metrology and Technology Department National Institute of Standards (NIS) El‐Giza Egypt
| | - Mohammed Abd‐Elbasseer
- Department of Acoustics, Mass and Force Metrology Division National Institute of Standards(NIS) El‐Giza Egypt
| | - Tarek M.El‐Basheer
- Department of Acoustics, Mass and Force Metrology Division National Institute of Standards(NIS) El‐Giza Egypt
| |
Collapse
|
6
|
Biomass and Lipid Productivity by Two Algal Strains of Chlorella sorokiniana Grown in Hydrolysate of Water Hyacinth. ENERGIES 2021. [DOI: 10.3390/en14051411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hydrolysate prepared from the chemical hydrolysis of water hyacinth biomass contains a high amount of solubilised carbohydrate and nutrients. This hydrolysate was utilised as a medium for the cultivation of two strains of Chlorella sorokiniana, isolated from a municipal wastewater treatment plant using two different media, i.e., BG-11 and Knop’s medium. Different light intensities, light–dark cycles, and various concentrations of external carbon sources (monosaccharides and inorganic carbon) were used to optimise the microalgal growth. For the accumulation of lipids and carbohydrates, the microalgal strains were transferred to nutrient amended medium (N-amended and P-amended). It was observed that the combined effect of glucose, inorganic carbon, and a 12:12 h light–dark cycle proved to be the optimum parameters for high biomass productivity (~200 mg/L/day). For Chlorella sorokiniana 1 (isolated from BG-11 medium), the maximum carbohydrate content (22%) was found in P-amended medium (N = 0 mg/L, P: 3 mg/L), whereas, high lipid content (17.3%) was recorded in N-amended medium (N = 5 mg/L, P = 0 mg/L). However, for Chlorella sorokiniana 2 (isolated from the Knop’s medium), both lipid (17%) and carbohydrate accumulation (12.3%) were found to be maximum in the N-amended medium. Chlorella sorokiniana 2 showed a high saturated lipid accumulation compared to other strains. Kinetic modelling of the lipid profile revealed that the production rate of fatty acids and their various constituents were species dependent under identical conditions.
Collapse
|
7
|
The Benefits of Water Hyacinth (Eichhornia crassipes) for Southern Africa: A Review. SUSTAINABILITY 2020. [DOI: 10.3390/su12219222] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Globally, water hyacinth is a known invasive species that predominantly threatens the pillars of sustainability. The cost of controlling these invasive plants is high and many Southern African countries are barely equipped for this liability as the process has to be performed over time. Despite this challenge, there is valuable resource recovery from water hyacinth which can be used to make financial and environmental returns. The visible differences between the control and utilisation methods lie in the definition, recognition, and matching of costs and benefits. Using a rapid appraisal of existing literature, which was analysed using meta-analysis, the current paper is an attempt to discuss the beneficial use of water hyacinth. It is argued in the paper that the economic feasibility of control methods which, on one hand, are used to calculate the economic value of water hyacinth, mainly relies on assumptions whose reliability and sustainability are questionable, thus implying limitations on using this kind of control methods. On the other hand, the costs and benefits of utilising water hyacinth can be quantifiable, making them susceptible to changes associated with time value and sensitivity analysis of possible fluctuations in cashflows. In the context of these annotations, other scholars have argued for the consideration of other utilisation alternatives, among which is included biogas which has been identified as the most viable option because of its potential in diversifying the energy mix, reducing greenhouse gas emissions, and contributing to improved water quality. Given these observations, this paper aims to contribute to policy and research discussions on the fiscal understandings of the material recovery from water hyacinth to promote the adoption of biogas technology. These views are discussed within the broader discourse of the sustainable development goals (SDGs).
Collapse
|
8
|
Eco-friendly magnetic activated carbon nano-hybrid for facile oil spills separation. Sci Rep 2020; 10:10265. [PMID: 32581282 PMCID: PMC7314835 DOI: 10.1038/s41598-020-67231-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 05/14/2020] [Indexed: 11/18/2022] Open
Abstract
This work focuses mainly on environmental concern and protection through providing beneficial use of waste biomass from water hyacinth to produce economical nano-magnetic adsorbent material-efficient for facile oil spill separation via an external magnetic field. The water hyacinth roots showed higher oil spills adsorption affinity of 2.2 g/g compared with 1.2 g/g for shoots. Nano-activated carbon was successfully extracted from the roots of water hyacinth after alkaline activation and followed by zinc chloride treatment before its carbonization. Nano-magnetite was induced into the activated carbonized nanomaterials to synthesized nano-magnetic activated carbon hybrid material (NMAC). X-ray diffraction elucidated the crystalline nature of both extracted activated carbon from water hyacinth and its magnetic hybrid material. Scanning electron microscopic micrographs implied the nano-size of both prepared activated carbon and the magnetite hybrid materials. The magnetic properties of the fabricated nano-magnetic activated carbon were evaluated using the vibrating sample magnetometer. The magnetic nano-hybrid material recorded a maximum oil adsorption affinity of 30.2 g oil/g. The optimum oil spill of 80% was established after 60 min in the presence of 1 g/L of magnetic nano-hybrid. The magnetic nano-hybrid material that absorbs oil spills was separated from the treatment media easily using an external magnetic field.
Collapse
|
9
|
Pakdeedachakiat W, Phruksaphithak N, Boontawan A. Pretreatment of mulberry stem by cholinium-based amino acid ionic liquids for succinic acid fermentation and its application in poly(butylene) succinate production. BIORESOURCE TECHNOLOGY 2019; 291:121873. [PMID: 31377506 DOI: 10.1016/j.biortech.2019.121873] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/21/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
Cholinium-glycinate ([Ch][Gly]) and cholinium-alanate ([Ch][Ala]) were investigated on the pretreatment of mulberry stem (MS). It resulted in an increase of glucose from 14% to more than 74% compared to the untreated sample. Pretreatment by reused [Ch][Gly] showed good performance for delignification of >60%, and improved structural polysaccharide digestion. Each fractional component has high potential for lignin purification, and succinic acid fermentation. The extracted lignin with [Ch][Gly] showed >90% purity with good qualities of aromatic unit as confirmed by FT-IR and 1H NMR spectra. The carbohydrate rich material was employed for succinic acid fermentation with the highest yield of succinic acid more than 0.89 gsuccinic acid/gglucose. After purification, poly(butylene) succinate (PBS) was synthesized, and was characterized in comparison to commercial PBS.
Collapse
Affiliation(s)
- Woranud Pakdeedachakiat
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand
| | - Nantharat Phruksaphithak
- Department of Chemistry, Faculty of Science, Thaksin University, 222 Moo 2, Baan Prao Sub-District, Papayom District, Phatthalung 93110, Thailand
| | - Apichat Boontawan
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand; Center of Excellent in Agricultural Product Innovation, Suranaree University of Technology, 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand.
| |
Collapse
|
10
|
Enhancing enzymatic hydrolysis yield of sweet sorghum straw polysaccharides by heavy ion beams irradiation pretreatment. Carbohydr Polym 2019; 222:114976. [DOI: 10.1016/j.carbpol.2019.114976] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 06/03/2019] [Accepted: 06/06/2019] [Indexed: 02/07/2023]
|
11
|
Pretreatment Efficiency Using Autoclave High-Pressure Steam and Ultrasonication in Sugar Production from Liquid Hydrolysates and Access to the Residual Solid Fractions of Wheat Bran and Oat Hulls. Appl Biochem Biotechnol 2019; 190:166-181. [PMID: 31309413 DOI: 10.1007/s12010-019-03092-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 07/05/2019] [Indexed: 10/26/2022]
Abstract
The objective of this study was to evaluate the combination of physical and chemical pretreatments of wheat bran (WB) and oat hulls (OH) to obtain fermentable sugars and a residual solid fraction with increased susceptibility to enzymatic hydrolysis. High-pressure steam in an autoclave and ultrasonication were employed as pretreatments, and for both processes, WB and OH were treated with sulfuric acid (H2SO4), neutral medium (H2O) and sodium hydroxide (NaOH). Autoclave high-pressure steam in an acid medium was the most effective for the release of sugars (total sugars, xylose and glucose) from liquid hydrolysates and for the modification of the residual solid fraction. The cellulose content of the WB residual solid fraction increased from 7.19 to 39.17%, the lignin fraction of WB decreased from 6.40 to 3.21%, the cellulose content of OH increased from 31.16 to 61.53%, and lignin fraction of OH decreased from 18.12 to 7.24%, resulting in materials more susceptible to enzymatic hydrolysis.
Collapse
|
12
|
Structure and distribution changes of Eucalyptus hemicelluloses during hydrothermal and alkaline pretreatments. Int J Biol Macromol 2019; 133:514-521. [DOI: 10.1016/j.ijbiomac.2019.04.127] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 04/13/2019] [Accepted: 04/16/2019] [Indexed: 11/19/2022]
|
13
|
Technological Processes for Conversion of Lignocellulosic Biomass to Bioethanol. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2017. [DOI: 10.22207/jpam.11.4.27] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
14
|
Zhang Y, Shen Y, Zhang H, Wang L, Zhang H, Qian H, Qi X. Isolation, purification and identification of two antioxidant peptides from water hyacinth leaf protein hydrolysates (WHLPH). Eur Food Res Technol 2017. [DOI: 10.1007/s00217-017-2941-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
15
|
Nguyen Thi BT, Ong LK, Nguyen Thi DT, Ju YH. Effect of subcritical water pretreatment on cellulose recovery of water hyacinth ( Eichhornia crassipe). J Taiwan Inst Chem Eng 2017. [DOI: 10.1016/j.jtice.2016.12.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
16
|
Ranjan A, Singh S, Malani RS, Moholkar VS. Ultrasound-assisted bioalcohol synthesis: review and analysis. RSC Adv 2016. [DOI: 10.1039/c6ra11580b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The present article highlights the efficacy of ultrasound in the intensification of all the steps of bioalcohol synthesis with a critical analysis of the literature.
Collapse
Affiliation(s)
- Amrita Ranjan
- Center for Energy
- Indian Institute of Technology Guwahati
- Guwahati-781 039
- India
- Instituto de Biología Molecular y Celular de Plantas (IBMCP)
| | - Shuchi Singh
- Center for Energy
- Indian Institute of Technology Guwahati
- Guwahati-781 039
- India
| | - Ritesh S. Malani
- Center for Energy
- Indian Institute of Technology Guwahati
- Guwahati-781 039
- India
| | - Vijayanand S. Moholkar
- Center for Energy
- Indian Institute of Technology Guwahati
- Guwahati-781 039
- India
- Department of Chemical Engineering
| |
Collapse
|
17
|
Prospects for Irradiation in Cellulosic Ethanol Production. BIOTECHNOLOGY RESEARCH INTERNATIONAL 2015; 2015:157139. [PMID: 26839707 PMCID: PMC4709612 DOI: 10.1155/2015/157139] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 11/16/2015] [Indexed: 11/24/2022]
Abstract
Second generation bioethanol production technology relies on lignocellulosic biomass composed of hemicelluloses, celluloses, and lignin components. Cellulose and hemicellulose are sources of fermentable sugars. But the structural characteristics of lignocelluloses pose hindrance to the conversion of these sugar polysaccharides into ethanol. The process of ethanol production, therefore, involves an expensive and energy intensive step of pretreatment, which reduces the recalcitrance of lignocellulose and makes feedstock more susceptible to saccharification. Various physical, chemical, biological, or combined methods are employed to pretreat lignocelluloses. Irradiation is one of the common and promising physical methods of pretreatment, which involves ultrasonic waves, microwaves, γ-rays, and electron beam. Irradiation is also known to enhance the effect of saccharification. This review explains the role of different radiations in the production of cellulosic ethanol.
Collapse
|
18
|
Thomsen ST, Londoño JEG, Schmidt JE, Kádár Z. Comparison of Different Pretreatment Strategies for Ethanol Production of West African Biomass. Appl Biochem Biotechnol 2014; 175:2589-601. [DOI: 10.1007/s12010-014-1444-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/08/2014] [Indexed: 11/28/2022]
|
19
|
Perspective and prospective of pretreatment of corn straw for butanol production. Appl Biochem Biotechnol 2014; 172:840-53. [PMID: 24122704 DOI: 10.1007/s12010-013-0548-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
Corn straw, lignocellulosic biomass, is a potential substrate for microbial production of bio-butanol. Bio-butanol is a superior second generation biofuel among its kinds. Present researches are focused on the selection of butanol tolerant clostridium strain(s) to optimize butanol yield in the fermentation broth because of toxicity of bio-butanol to the clostridium strain(s) itself. However, whatever the type of the strain(s) used, pretreatment process always affects not only the total sugar yield before fermentation but also the performance and growth of microbes during fermentation due to the formation of hydroxyl-methyl furfural, furfural and phenolic compounds. In addition, the lignocellulosic biomasses also resist physical and biological attacks. Thus, selection of best pretreatment process and its parameters is crucial. In this context, worldwide research efforts are increased in past 12 years and researchers are tried to identify the best pretreatment method, pretreatment conditions for the actual biomass. In this review, effect of particle size, status of most common pretreatment method and enzymatic hydrolysis particularly for corn straw as a substrate is presented. This paper also highlights crucial parameters necessary to consider during most common pretreatment processes such as hydrothermal, steam explosion, ammonia explosion, sulfuric acid, and sodium hydroxide pretreatment. Moreover, the prospective of pretreatment methods and challenges is discussed.
Collapse
|
20
|
Baral NR, Shah A. Microbial inhibitors: formation and effects on acetone-butanol-ethanol fermentation of lignocellulosic biomass. Appl Microbiol Biotechnol 2014; 98:9151-72. [DOI: 10.1007/s00253-014-6106-8] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/15/2014] [Accepted: 09/16/2014] [Indexed: 12/26/2022]
|
21
|
Coban I, Sargin S, Celiktas MS, Yesil-Celiktas O. Bioethanol production from raffinate phase of supercritical CO2 extracted Stevia rebaudiana leaves. BIORESOURCE TECHNOLOGY 2012; 120:52-59. [PMID: 22784953 DOI: 10.1016/j.biortech.2012.06.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 06/17/2012] [Accepted: 06/18/2012] [Indexed: 06/01/2023]
Abstract
The extracts of Stevia rebaudiana are marketed as dietary supplements and utilized as natural sweetening agent in food products. Subsequent to extraction on industrial scale, large quantities of solid wastes are produced. The aim of this study was to investigate the bioconversion efficiency of supercritical CO(2) extracted S. rebaudiana residues. Therefore, leaves were extracted with supercritical CO(2) and ethanol mixture in order to obtain glycosides, then the raffinate phase was hydrolyzed by both dilute acid and various concentrations of cellulase and β-glucosidase cocktail. The maximum yield of reducing sugars reached 25.67 g/L under the optimal conditions of enzyme pretreatment, whereas 32.00 g/L was reached by consecutive enzymatic and acid hydrolyses. Bioethanol yield (20 g/L, 2.0% inoculum, 2 days) based on the sugar consumed was 45.55% corresponding to a productivity of 0.19 kg/m(3)h which demonstrates challenges to be utilized as a potential feedstock for the production of bioethanol.
Collapse
Affiliation(s)
- Isik Coban
- Department of Bioengineering, Faculty of Engineering, Ege University, 35100 Bornova-Izmir, Turkey
| | | | | | | |
Collapse
|