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. 2022 Jul 18;12(9):178. doi: 10.1007/s13205-022-03234-y

Bioethanol production from Ficus fruits (Ficus cunia) by Fusarium oxysporum through consolidated bioprocessing system

Grihalaksmi Devi Nongthombam 1, Prakash Kumar Sarangi 2,✉, Thangjam Anand Singh 2,✉, Chandradev K Sharma 1, Narayan C Talukdar 3
PMCID: PMC9294110  PMID: 35865259

Abstract

Fusarium oxysporum is among the few filamentous fungi capable of fermenting ethanol directly from lignocellulose biomass (LCB). It has the essential enzymatic toolbox to disintegrate LCB to its monosaccharides, which subsequently fermented to ethanol under anaerobic and micro-aerobic conditions. However, the structural complexity of LCB and modest performances of wild fungi are major limitations for application in local biorefineries. This study assessed the potential of the locally isolated Fusarium oxysporum for the production of bioethanol from Ficus fruits (Ficus cunia) using Consolidated Bioprocessing (CBP). The maximum ethanol concentration achieved was at 5% substrate loadings with pH 6 irrespective of temperature variance, attaining a concentration of 3.54 g/L and 3.88 g/L at 28 °C and 32 °C, respectively. The monitoring of analytes (glucose, arabinose, cellobiose, xylose, acetic acid, ethanol, furfural, and HMF) in this study suggests the utilization of an array of sugars released from Ficus fruits, irrespective of the difference in the process parameters. This study also shows that CBP of freshly grounded Ficus fruits was feasible employing a mild hydrothermal pretreatment (autoclaved at 121 °C for 30 min in 1:10 w/v) and without supplementing any extraneous enzymes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03234-y.

Keywords: Fusarium oxysporum, Ethanol, Consolidated bioprocessing: waste, Enzymes

Introduction

Cellulosic ethanol represents a significant substitute to meet the global demand for renewable liquid transportation fuels (Puri et al. 2012; Sarangi and Nanda 2020a; Ahmed et al. 2019; Niphadkar et al. 2018). Lignocellulose biomass (LCB) is an attractive feedstock due to its abundant availability, low cost, and promising environmental benefits, for the production of cellulosic ethanol, as it does not compete directly with food crops (Schuster and Chinn 2012; Sharma et al. 2015; Sarangi and Nayak 2021). However, their highly recalcitrant nature makes the conversion of cellulose and hemicellulose to fermentable sugars, a rate-limiting step. The intricate molecular design of LCB has evolved over 400 million years ago and retained since then to protect plants from other organisms. Consequently, pretreatment is necessary by the addition of costly cellulolytic enzymes before fermentation, which significantly increases the expenses of bioprocessing (Lynd et al. 2005; Sarangi and Nanda 2020b; Beig et al. 2021). Hydrothermal pretreatment of LCB is a recognized environment-friendly process that ameliorates the enzymatic saccharifcation of cellulose rendering the solubilization of hemicellulose as hemicellulosic-derived compounds (Biswas et al. 2020; Thamarys et al. 2021).

Consolidated Bioprocessing (CBP) accomplishes in a single vessel, producing cellulolytic enzymes, hydrolysis of LCB, and fermentation of resulting sugars (C5 and C6) to ethanol, or other valuable products, simplifying process complexity. Therefore, CBP is an economical approach for second-generation biofuel production (Olguin-Maciel et al. 2019; Singh et al. 2017; Sarangi and Nanda 2019). This single-step conversion method relies on a potential CBP microbe or microbial consortia, possessing combined hydrolytic and fermentation ability. The cost-effectiveness is determined for industrially relevant targets of CBP-based cellulosic ethanol production with the productivity of ~ 1 g L−1 h−1or titer of > 40 g L−1 corresponding to a yield of greater than 90% of the theoretical maximum (Dien et al. 2003). However, to date, no single candidate microorganism with such significant potential is reported (Akinosho et al. 2014). Considering this, a broad screening of diverse environments for cellulose-degrading fungi with efficient bioconversion of LCB to bioethanol and the identification of novel strains is important for strengthening the viability of a CBP approach. Improved ethanol production from the local LCB is of paramount importance for sustainable CBP.

Renewable resources act as sustainable resources and can also aid in economic development with current energy requirement and also achieve eco-friendly environment (Sarangi et al. 2020b). Thus, exploration of such novel renewable sources can be emphasized for biosynthesis of biofuel energy and bioproducts/biochemicals for long time in sustainable modes. Global level, renewable, green nature bioresources have been explored and utilized for different types of biofuel synthesis (i.e., bioethanol, biobutanol, biogas, isopropanol and also biodiesel) those help in mitigation fossil based fuels consumption and its impact on environment (Madu and Agboola, 2018; Das et al. 2016; Sarangi et al. 2020a; Siang et al. 2020). The utilization of corn stover, rice straw, sugarcane bagasse, and wheat straw as feedstock is gaining popularity worldwide towards the production of a wide array of bioenergy and value-added bioproducts/biochemicals via different pathways and enzymatic hydrolysis/converting nature (Mehta et al. 2022; Mondal et al. 2021; Srivastava et al. 2021; Sarangi and Nanda 2020c; Yadav et al. 2021, Pattnaik et al. 2021). Conversion of such waste materials could lead to a bio-based economy. One crucial aspect of bioethanol production is the year-round availability of raw materials. Feedstock supply for bioethanol production has season variability depending on geographic locations. LCB is a prominent feedstock from agricultural residues, forest-based woody materials, and municipal wastes towards bioethanol production due to its high availability and low cost, even though, has not yet, been established on a commercial scale.

The feedstock used in this study was from an 11-year-old Ficus cunia plant. It bore fruits in five phases during the studied period from July 2012 to August 2013 during which the yield per fruiting ranged from 97 to 256 kg. Traditionally, in Manipur, the fruit is dedicated to death and is named Ashi Heibong in native Manipuri, and accordingly, only half of the fruit is consumed and the rest were thrown away for the deceased ancestors. However, the younger generations do not consume and are usually left to rot as it ripens. The potential of fungi for biomass degradation has been acknowledged through several studies and applications, starting from recognizing their innate potential of forest litter-decay isolates to the engineering of versatile enzymatic pools for biorefinery (Lange et al. 2019; Ali et al. 2016). Hence, a Fusarium oxysporum strain isolated from a sacred grove of Manipur is explored for bioethanol production from Ficus fruits through the CBP approach. The sugars (arabinose, cellobiose, glucose, and xylose) and inhibitors (acetic acid, furfural, and hydroxymethyl-furfural (HMF)) were monitored during fermentation to understand the preference of sugars and the formation of byproducts.

Materials and methods

Reagents and chemicals

All chemicals used in this study were of analytical grade obtained from Sigma-Aldrich, (Bengaluru, KA, India), Himedia (India), and Merck Limited (New Delhi, India). For DNA isolation, chemicals used were of molecular biology grade. For HPLC (High-Pressure Liquid Chromatography) assay, water and H2SO4 used were HPLC Grade from Rankem (India). All standards used in HPLC are purchased from Absolute Standards (USA).

Sampling site and fungal isolation and its identification

Litter soil samples were collected from a sacred grove at Heingang Marjing (N 24°52′35.2′′; E 093°57′01.0′′; altitude 834 m) situated in North-Hill base, Manipur, India. Fusarium oxysporum strain used in the study has been isolated from this litter soil employing standard procedures as described by Leslie and Summerell (2006).

Fungal genomic DNA extraction was performed using the rapid extraction method as described by Cenis (1992). For molecular characterization, amplification of the ITS1-5.8S-ITS2 rDNA region through PCR using the primer set: pITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and pITS4 (5′-TCCTCCGCTTATTGATATGC-3′) in a C1000™ Touch Thermal Cycler (BIORAD, USA). The cycling condition was programmed with an initial denaturation of 5 min at 95 °C, followed by 35 cycles at 95 °C for 1 min, 52 °C for 1 min and 72 °C for 1 min, with a final extension of 5 min at 72 °C and infinite hold time at 4 °C completed the run. The amplified products were verified in 1.5% agarose gel and visualized using ethidium bromide in ChemiDoc™ MP Imaging System (BIORAD, USA). Amplicons of about 430–580 bp thus obtained were sequenced with an ABI 3130 genetic analyzer (Applied Biosystems) at Merck specialists, Bangalore, India. The ITS1-5.8S-ITS2 rDNA region sequence of the strain was compared with the sequences of type strains available in the GenBank database using NCBI BLAST server (http://blast.ncbi.nlm.nih.gov/Blast/; National Centre for Biotechnology Information, MD, USA). The ITS1-5.8S-ITS2 rDNA region sequence was submitted to GenBank with nucleotide accession number KR920738.

Estimation of soluble extractives, cellulose, hemicelluloses and lignin content of biomass

The Ficus fruits collected from the premises of the Institute of Bioresources and Sustainable Development, Manipur, India were analyzed for soluble extracts, cellulose, hemicelluloses, and lignin contents and expressed as a percentage on a dry weight basis. The soluble extractives were determined using a protocol as described by Lima et al. (2014). Cellulose and hemicellulose were measured using a modification of the protocol employed by Updegraff (1969) and estimated using an o-Toluidine reagent, as described by Goodwin (1970). For lignin, estimated in terms of total phenol using Folin Ciocalteu reagent following the protocol described by Singleton and Rossi Jr (1965).

Pretreatment of lignocellulosic substrate

The freshly grounded Ficus fruits (Ficus cunia) were pretreated by adopting hydrothermal pretreatment (da Cruz et al. 2012) with some modifications. The pretreatment reactions were prepared by combining 10 g of biomass with 100 ml distilled water (1:10 ratio) and autoclaved at 121 °C for 30 min.

Bioethanol production

Fusarium oxysporum HG19 strain (KR920738) employed for fermentation of hydrothermally pretreated Ficus fruits supplemented with T1 minimal media in this study via CBP for ethanol production. Fungal mycelium was grown for 5 days on Potato Dextrose Agar (PDA) plates. Mycelial discs of 0.3 mm2 (4 nos.) were harvested using sterile cork borer from the periphery and used as inoculum. Fermentation was carried out statically, in 50 ml conical flask containing 30 ml T1 medium substituted with fruits as the sole carbon source at a different set of parameters for optimization under this study. Sample of 2 ml per sampling initiated after 48 h, with an interval of 24 h in aseptic conditions and was stored at − 20 °C until further use. All samples withdrawn were centrifuged at 10,000g for 10 min at 4 °C. For HPLC system (Agilent Technologies Inc., USA), the supernatants obtained were filtered aseptically, through 0.2 µm filters, and analyzed for ethanol, sugars, carboxylic acids, and phenolic derived compounds produced during fermentation. All samples were in triplicates.

Optimization of process parameters

Effect of substrate loadings

Substrate loadings with the range of 3, 4, and 5% w/v were studied to observe their influence on ethanol yield during fermentation under the same set of process parameters.

Effect of pH

The effect of pH was studied under the other process parameters being kept constant and employing a pH range of 4, 5, and 6, since most of the fermentation occurred in acidic conditions. The pH was adjusted using 10% filter sterilized tartaric acid.

Effect of temperature

To study the effect of temperature, fermentation was performed with other parameters kept constant and varied at two sets of temperature conditions: 28 °C and 32 °C.

Analysis of sugars, ethanol, and byproducts

HPLC (Agilent HPLC 1200 Series) performed monosaccharide and disaccharide analysis using Aminex HPX-87H anion-exchange column (300 × 7.8 mm, Bio-Rad) equipped with cation-H guard cartridge (Bio-Rad). The filtered (0.22 µm pore size, Millipore) and degassed mobile phase (5 mM H2SO4) was used at a constant flow rate of 0.6 ml/min with the column and RI (refractive index) detector temperatures maintained at 40 °C and 50 °C, respectively. All standards of the sugars (Absolute Standards, USA) at 0.2–1.0 g/L were separated individually and quantified using external calibration with an equimolar mixture (cellobiose, glucose, xylose, and arabinose), and the areas obtained were used to calculate the concentration of monosaccharides and disaccharide in the test samples. Similarly, the standard curves were generated using acetic acid, furfural, HMF, and ethanol (Absolute Standards, USA) from the equimolar mixture after attaining separate retention times when run individually in the concentration ranging from 0.2 to 1.0 g/L.

Results

Composition analysis

Ficus fruits composition analysis resulted in a rich fraction of ethanol-soluble extractives as high as 4.67 ± 0.57, which constitutes a good non-structural source for the initial growth of fungi (Table 1). The structure of this biomass is with lignin up to 17.1 ± 0.73% (on a Dry Weight basis). Besides, the cellulose and hemicellulose account for 34.09 ± 0.41 and 25.25 ± 0.62% (DW) of the total biomass, respectively, demonstrating its suitability as feedstock for bioethanol production. Detailed results of the compositional parameters are summarized in Table 1.

Table 1.

Composition of Ficus fruits (Ficus cunia) used in this study

LCB Components of the biomass (%)
Soluble Cellulose Hemicellulose Lignin
Ficus fruits 4.67 ± 0.57 34.09 ± 0.41 25.25 ± 0.62 17.17 ± 0.73
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Data represented are the averages of the results from duplicated experiments with three replicates each (bar indicates ± SD)

Optimization of fermentation parameters for enhanced ethanol production

Fermentation activity was performed for enhanced ethanol production at different doses of substrates with varied parameters. In this part of the study, change in ethanol and other analytes concentrations were investigated as a measure of ethanol production ability at varied process parameters for optimization (pH, temperature, incubation time, and substrate concentrations) by F. oxysporum HG19 strain, from freshly grounded and hydrothermally pretreated Ficus fruits (1:10 w/v at 121 °C for 30 min in an autoclave). The concentrations of arabinose, cellobiose, glucose, xylose, acetic acid, ethanol, furfural, and HMF were monitored to determine their concentrations during the course of fermentation (see Fig. 1).

Fig. 1.

Fig. 1

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Ficus fruit (Ficus cunia) yield per fruiting phase during our study

Fusarium oxysporum HG19 strain initially show an increase in the concentrations and yields of ethanol up to 48 h and gradually declined with time [Supplementary Figs. 1–4]. The maximal ethanol concentration achieved was 3.88 g/L (Fig. 3E). Fermentation time of 48 h was optimal for F. oxysporum HG19 strain after which the concentration of bioethanol gradually declined in the fermentation process of CBP at static flask condition. Initially, glucose consumption was rapid, and the same pattern of glucose consumption, during fermentation was observed with the difference of inability to detect after 72 h. Acetic acid production fluctuated with the maximum production of 8.85 g/L at 48 h (Fig. 2E), which declines with the passage of time during fermentation. Cellobiose concentration initially increased slightly and decreased although, insignificantly during the course of fermentation, which may be attributed to the cellulolytic action by F. oxysporum HG19 strain on cellobiose to release glucose units from the Ficus fruits and consumed simultaneously in maintaining their metabolic activities. Xylose consumption started after 72 h with the complete exhaustion of glucose. In the case of arabinose, the concentration remains more or less constant during all the bioprocesses involving F. oxysporum HG19 strain indicating its low consumption to affect ethanol production. Similarly, the concentration for both furfural and HMF remains constant throughout the process irrespective of the set operational parameters.

Fig. 3.

Fig. 3

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Ethanol production from fresh Ficus fruits (hydrothermally treated) and monitoring of analytes concentrations (acetic acid, arabinose, cellobiose, furfural, glucose, HMF, and xylose) during the course of fermentation at 5% (w/v) loadings at pH 4, pH 5 and pH 6 respectively by HG19 (Fusarium oxysporum strain), maintained at 32 °C. A–F represent one set of each experiment

Fig. 2.

Fig. 2

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Ethanol production from fresh Ficus fruits (hydrothermally treated) and monitoring of analytes concentrations (acetic acid, arabinose, cellobiose, furfural, glucose, HMF, and xylose) during the course of fermentation at 5% (w/v) loadings at pH 4, pH 5 and pH 6 respectively by HG19 (Fusarium oxysporum strain), maintained at 28 °C. A–F represent one set of each experiment

Effect of pH

It was observed an increment in concentrations and yields of bioethanol produced with an increase up to pH 6 (Figs. 2, 3). The highest bioethanol titre and yield were detected at pH 6. The maximal bioethanol titre obtained was 3.88 g/L by F. oxysporum HG19 strain from hydrothermally pretreated Ficus fruits. The maximum yield of bioethanol was determined as 78 mg/g of hydrothermally pretreated Ficus fruits as substrate. Therefore, pH 6 was found to be optimal for bioethanol production from hydrothermally pretreated Ficus fruits with F. oxysporum HG19 tested through CBP from the simple flask experiment at the laboratory scale.

Effect of temperature

The effect of temperature on ethanol yield was investigated at 28 °C and 32 °C taking into consideration the ambient temperature of the Imphal valley during summer, to deduce the expenses required for regulation. The ethanol yield slightly increased at 32 °C comparatively from 28 °C from the fermentation experiments conducted using F. oxysporum HG19 strain irrespective of pH and substrate concentrations (Figs. 2, 3). The maximal ethanol concentrations achieved at 28 °C and 32 °C by F. oxysporum HG19 strain were 3.54 g/L and 3.88 g/L, respectively. Elevation in acetic acid production was observed at a higher temperature accompanied with acceleration in glucose uptake rate, which was evident with a higher growth rate.

Effect of substrate concentrations

Substrate loading concentrations were tested from 3% up to 5% w/v on fresh weight of Ficus fruits in experiments conducted in Erlenmeyer flasks for ethanol production. For F. oxysporum HG19 strain, ethanol production increases with a hike in substrate loadings and attained maximum ethanol production at substrate loading concentrations of 5% w/v. Furthermore, the ethanol concentration increased with the rise in substrate loadings but the increase in ethanol yield (g EtOH per g of substrate addition) is insignificant. The maximum ethanol titre attained was 3.88 g/L corresponding to 0.08 g EtOH per g of Ficus fruits with pH 6 at 32 °C (Figs. 2, 3).

Discussion

Fusarium oxysporum is among the few microbial species that are acknowledged for possessing the enzymatic systems required to disintegrate cellulose and hemicellulose and subsequently ferment the generated hexoses and pentose sugars to bioethanol in a single step (Ali et al. 2012; Panagiotou et al. 2005b; Christakopoulos et al. 1989). Other associated characteristics such as high levels of cellulases and xylanases produced by F.oxysporum, render it efficient for the CBP of LCB to bioethanol. The F.oxysporum HG19 exhibit high levels of cellulases and xylanases activities on different LCB substrates and produced ethanol efficiently (data not shown). This strain is tolerant to high levels of sugars, ethanol, and inhibitors such as acetate (Hennessy et al. 2013; Singh and Kumar 1991) and thus supports CBP. Glucose fermentation mediated by F. oxysporum remained unaffected until ethanol concentrations reach 4.5–5.0% in the reactor (Enari and Suihko 1983). Growing cells of F. oxysporum are capable of reducing acetate to ethanol, a major inhibitory compound produced by microbes during the ethanol fermentation process (Enari and Suihko 1983). The structural and compositional changes brought about by hydrothermal pretreatment of Ficus fruits ascertained it to be an efficient method. Scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and HPLC data analysis established the releasing of desirable amounts of fermentable sugars and inhibitors within the permissible limit for subsequent enhancement in the enzymatic saccharification to yield bioethanol upon fermentation as shown in our previous work (Nongthombam et al. 2017). Similarly, the mild hydrothermal pretreatment (autoclaved at 121 °C for 30 min in 1:10 w/v) of freshly grounded Ficus fruits was feasible without supplementing any extraneous enzymes. The monitoring of analytes (glucose, arabinose, cellobiose, xylose, acetic acid, ethanol, furfural, and HMF) documented in this study elucidates the similar utilization pattern of sugars irrespective of the difference in the process parameters.

Xylose consumption started only after 72 h with the complete exhaustion of glucose, which is more preferential, since it is unable to utilize xylose due to the presence of a significant amount of residual glucose or the presence of other inhibitory fermentative metabolites. Here in this study, also simultaneous utilization of xylose and glucose was demonstrated limited by the inhibitory effect of xylose uptake by glucose metabolism (Panagiotou et al. 2005c). In the case of arabinose, the concentration remains more or less constant during the bioprocesses involving HG19 indicating its low consumption to affect ethanol production. Our results are in accordance with previous studies that described that insignificant convertibility of arabinose to ethanol by F. oxysporum (Panagiotou et al. 2005c) and the yeasts (Fonseca et al. 2007). Furfural and HMF concentrations remained constant and slightly decreased at the end of fermentation, probably due to conversion to other smaller compounds.

pH greatly affects the fermentation of LCB and bioethanol yield. Deviation from the optimal pH value led to a reduction in bioethanol yield significantly similar to the earlier reports, which attributed to elevated energy requirements for maintaining fungal metabolic activities associated with the occurrence of a high death rate (Pclczar et al. 2004), though the possibility of other factors could not be ruled out. F. oxysporum HG19 strain does not co-metabolise xylose with glucose during anaerobic growth and starts xylose consumption only after exhaustion of glucose, which was in the line of earlier studies. Xylitol is the major product of xylose metabolism under anaerobic conditions (Panagiotou et al. 2005c), the ethanol production remains stagnant, while xylitol production could have taken place during xylose fermentation. Henceforth, a metabolic engineering approach to block the acetate and xylitol pathway may dramatically boost bioethanol yield via CBP by F. oxysporum.

Mixed sugars derived from LCB are depleted sequentially, as observed in Figs. 2 and 3 (Supplementary Figs. 1–4), probably reducing the overall efficacy of the process due to carbon catabolite repression as catabolism of these pentose sugars is typically suppressed by glucose derived from cellulose (Stulke and Hillen 1999). Hence, this selective and consecutive utilization of mixed sugars attributed by most microbes renders the fermentation process complex and often a reduction in yields and productivity from the target LCB (Bothast et al. 1999).

Improvement of F. oxysporum is a requisite, despite its potential in terms of both ethanol production and tolerance for competing with the already established microorganisms particularly, Saccharomyces cerevisiae for bioethanol production. Therefore, the screening of F. oxysporum strains that tolerate and produce high concentrations of ethanol is the need of the hour. Genetic modifications and evolutionary engineering integrated with the development of novel bioprocessing setups would enable the production of ethanol above the limit of 4–5% (w/v) from LCB, a minimum prerequisite to realize a large-scale distillation process.

For a viable and sustainable bioprocessing industry, optimization in production costs is crucial. The valorization of locally abundant biomasses accompanied with the mining of highly biomass-induced fungal strains will induce sustainable CBP (Kim and Dale 2016; Antizar- Ladislao and Turrion-Gomez 2008). F. oxysporum has been demonstrated by earlier studies as a capable CBP-adapted fungus that decomposes LCB and converts to ethanol with yields, similar to simple glucose–xylose fermentation, under oxygen-limiting conditions (Panagiotou et al. 2003, 2005c). Furthermore, its potential to metabolize crystalline cellulose under simultaneous saccharification and fermentation has been confirmed with more prominent ethanol yields (Panagiotou et al. 2005b) and the use of nitrate as a nitrogen source attributed for those yields (da Rosa-Garzon et al. 2018; M’Barek et al. 2020). Less fungal mycelium growth on L-arabinose alone may be due to high levels of Glucose 6-Phosphate (G6P) in this fungus may indicate the absence of arabinose transport into the cell and to G6P channeling difficulties to the Pentose Phosphate pathway (Panagiotou et al. 2005a). Taking account of the above-mentioned cultural and metabolic factors, under oxygen-limiting conditions, F. oxysporum principally uses glucose and xylose liberated from LCB disintegration for bioethanol production, and hence, arabinose does not significantly contribute to the process as observed in our study (Figs. 2, 3). These findings finally highlighted the significance of this litter-decay wild fungus for high bioethanol production from the locally available Ficus fruits for consolidated and integrated bioethanol production.

Conclusions

The use of Ficus fruits as biomass could be an important factor towards developing sustainable biorefineries particularly in Manipur, India. Moreover, the availability of potent wild lignocellulolytic ascomycetes that could not only disintegrate it down but also convert it into bioethanol is with no doubt advantageous. Despite the LCB matrix recalcitrance, the F. oxysporum HG19 strain with its enzymatic diversity and potentials initiated lignin attack, penetrating the pores opening the cellulose microfibrils adopting hydrothermal pretreatment, and finally, decomposes and fermentation proceeds for bioethanol production from Ficus fruits. The ethanol yields produced by the wild-type strain from the sacred grove in the present study are encouraging and warrants attention for improvement in industrial application. The maximum ethanol concentration of 3.54 g/L and 3.88 g/L at 28 °C and 32 °C, respectively, were achieved. This strain displayed a single-step conversion of biomass that indicates its suitability as an ideal biocatalyst for the CBP approach from Ficus fruits.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (DOCX 389 kb) (389.5KB, docx)

Acknowledgements

For this manuscript there is no funding source(s). There is no any assistance of colleagues.

Abbreviations

LCB

Lignocellulose biomass

CBP

Consolidated bioprocessing

h

Hours

HMF

Hydroxymethyl-furfural

HPLC

High pressure liquid chromatography

HG19 strain Accession Number

KR920738

PDA

Potato dextrose agar

DW

Dry weight

EtOH

Ethanol

SEM

Scanning electron microscopy

FT-IR

Fourier transform-infrared spectroscopy

G6P

Glucose 6-phosphate

Funding

Not applicable.

Availability of data and material

Manuscript contains original research.

Code availability

Not applicable.

Declarations

Conflicts of interest/Competing interests

The authors have no conflicts of interest

Ethics approval

Not applicable.

Consent to participate

Not applicable.

Consent for publication

All authors gave consent for publication.

Footnotes

Accession numbers: The ITS1-5.8S-ITS2 rDNA region sequence submitted to GenBank with nucleotide accession number KR920738. (http://blast.ncbi.nlm.nih.gov/Blast/; National Centre for Biotechnology Information, MD, USA).

Contributor Information

Prakash Kumar Sarangi, Email: sarangi77@yahoo.co.in.

Narayan C. Talukdar, Email: nctalukdar@yahoo.com

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