Synthesis of methylcellulose-polyvinyl alcohol composite, biopolymer film and thermostable enzymes from sugarcane bagasse

https://doi.org/10.1016/j.ijbiomac.2023.123903Get rights and content

Highlights

  • Cellulose was extracted from sugarcane bagasse and converted into methylcellulose.

  • Composite of methylcellulose, polyvinyl alcohol and biopolymer film were synthesized.

  • By-products of process were used as a substrate for thermostable enzymes' production.

Abstract

Agro-industrial wastes and by-products are the natural and abundant resources of biomaterials to obtain various value-added items such as biopolymer films, bio-composites and enzymes. This study presents a way to fractionate and to convert an agro-industrial residue, sugarcane bagasse (SB), into useful materials with potential applications. Initially cellulose was extracted from SB which was then converted into methylcellulose. The synthesized methylcellulose was characterized by scanning electron microscopy and FTIR. Biopolymer film was prepared by using methylcellulose, polyvinyl alcohol (PVA), glutaraldehyde, starch and glycerol. The biopolymer was characterized to exhibit 16.30 MPa tensile strength, 0.05 g/m2 h of water vapor transmission rate, 366 % of water absorption to its original weight after 115 min of immersion, 59.08 % water solubility, 99.05 % moisture retention capability and 6.01 % of moisture absorption after 144 h. Furthermore, in vitro studies on absorption and dissolution of model drug by biopolymer showed 2.04 and 104.59 % of swelling ratio and equilibrium water content, respectively. Biocompatibility of the biopolymer was checked by using gelatin media and it was observed that swelling ratio was higher in initial 20 min of contact. The extracted hemicellulose and pectin from SB were fermented by a thermophilic bacterial strain, Neobacillus sedimentimangrovi UE25 that yielded 12.52 and 6.4 IU mL−1 of xylanase and pectinase, respectively. These industrially important enzymes further augmented the utility of SB in this study. Therefore, this study emphasizes the possibility for industrial application of SB to form various products.

Introduction

Currently, an increasing interest in environmentally friendly materials has motivated industrialists to develop and use biopolymers for various applications [1]. Cellulose, in general, is an almost inexhaustibly available and renewable natural polymer which is composed of anhydroglucose units linked by β-1,4 glycosidic bonds [2]. It can be transformed in to various substrates, ranging from nanoparticles to microfibers and from pulp to chemically derivatized polymers [3]. Derivatized cellulose polymers exhibit different functionalities and characteristics, for instance, extreme mechanical strength, thermo-responsivity, lyotropic liquid crystallinity, water solubility and high surface charge, that depend on the derivatization methods [4].

Lignocellulosic materials such as sugarcane bagasse (SB) are the largest resource of cellulose. Sugarcane crop is characterized for the highest bioconversion efficiency yielding 55 tons of dry matter per hectare of land annually [5]. The extraction of juice from sugarcane produces millions of tons of SB every year; it is estimated that ~280 kg of SB is generated for every ton of sugarcane [6]. By and large, the great potential of SB for various industrial applications has remained neglected and most of this residue is utilized as a low-grade fuel, as a raw material for chip-board and paper making, and as a basic material for animal feed [5]. The use of agricultural wastes to manufacture value-added materials is also appreciated as an effective way to decrease the waste disposal cost. The complex structure of plant cell wall is an impediment in extracting its components and hence the extraction of pure cellulose has remained the subject of detailed research for many years [7]. There are many reports describing the feasibility of recycling of cellulosic waste material to produce high-value products [8], [9], [10], [11]. Extracted components of SB can also be used as low cost substrates for the production of industrially important enzymes including cellulase, xylanase and pectinase [12]. Although, mesophilic fungi and bacteria have widely been used to produce industrially important enzymes by fermenting SB as a substrate [13], [14], thermophilic microbes have been recognized as source of the proteins exhibiting desirable compatibility and stability with harsh biorefinery processes [15].

In addition to its utilization as a fermentation raw material, cellulose can also be converted into important cellulose derivatives like esters by simple chemical modifications. The derivatives can further be converted to cellulose ethers, or can act as a precursor for the synthesis of regenerated textile films and fibers, and biologically degradable plastics [16]. Another commercially important derivative, methylcellulose, is widely applied in several areas including synthesis of painting and building materials, and in pharmaceuticals and food industries [17]. Indeed, cellulosic fiber is one of the most researched bio-based fillers to form biopolymer [8].

Petroleum based biopolymer generally possess good barrier, thermal and mechanical properties with relatively low cost and easy processability. However, the pollution problem associated with the widespread use of plastics has also been well described. Nonetheless, it is estimated that the plastic waste generation will rise to 12 billion metric tons by the year 2050 [18]. Therefore, it is important to look for alternatives in the form of biopolymer film by using cellulose. In addition to utilizing a cellulosic polymer in various applications, many a times, blending of two or more polymers produces materials with enhanced characteristics; blending indeed is a quick process compared to developing a new polymer [19]. In this context, polyvinyl alcohol (PVA) can be used as a copolymer with methylcellulose because of its hydrophilicity, safe-status, nonirritant nature, and desirable stability towards heat and chemicals [20]. Currently, PVA based materials are extensively utilized in the agriculture and in pharmaceutical and food industries [21]. Methylcellulose has good biocompatibility and biodegradability but poor mechanical properties. In contrast, PVA is a versatile polymer which possess higher mechanical properties [19]. Therefore, composites of methylcellulose and PVA have attracted considerable attention of researchers considering the synergic relation between the two polymers and possibility of developing novel blends with improved properties. Blending can also incur desirable attributes related to application of biopolymer such as improved moisture absorption capacity, moisture retention ability and water vapor permeability.

Considering the importance of fractions present in SB, this study was designed to utilize it in two different ways. First, the extracted components of SB were used to produce thermostable bacterial enzymes. Secondly, derivatized cellulose was used to form biopolymer film and composite. The study presents a prospect of utilizing SB with the concomitant production of valuable products.

Section snippets

Materials

Sugarcane bagasse (SB) was collected from a local sugar industry situated at Matiari, Sindh, Pakistan. All the mentioned media and chemicals were of analytical reagent grade and were procured from Dae-Jung Chemicals (South Korea), Sigma-Aldrich (Germany), and Oxoid (USA).

Preparation of Sugarcane bagasse

Bagasse was washed with tap water, dried, ground and then passed through the sieve of 300 μ mesh size [22].

Extraction of plant cell wall components

Extraction of components from SB was performed as mentioned by Szymanska-Chargot et al. [23] with slight modifications.

Structural analysis of extracted pectin and hemicellulose of bagasse

Fractionation of plant biomass is an initial step to isolate lignocellulosic components for subsequent valorization. Here, SB was fractionated, and the extracted components were investigated by SEM. SEM image presented a conserved and globular shape of the extracted pectin indicating the repulsion of water during lyophilization (Fig. 1a). Little crumple surface with minor particles was observed. With the effect of heating in extraction process, small bubbles appeared on the surface of pectin

Conclusion

This study proves the concept of conversion of sugarcane bagasse into valuable by-products. Surface morphology of extracted pectin, hemicellulose, cellulose and methylcellulose were analyzed by scanning electron microscopy. Extracted xylan from SB resulted in enhanced xylanase production as compared to the commercial substrate. Extracted cellulose was converted into methylcellulose and a porous polymer composite was synthesized by using polyvinyl alcohol through freeze drying method.

CRediT authorship contribution statement

RR performed experiments and analyze the data; UR wrote the intial draft and data curation; SA performed experiments; KKN performed experiments; AQ performed experiments; MS supervision and editing the final draft; STA analyze data; JTA, funding acquisition; AKA performed characterization; HMA, data curation.

Declaration of competing interest

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

Rozina Rashid reports financial support was provided by Higher Education Commission Pakistan. The financial support from Taif University Researchers Supporting Project is also declared.

Acknowledgements

The authors acknowledge the financial support from Taif University Researchers Supporting Project number (TURSP-2020/355), Taif University, Taif, Saudi Arabia.

References (62)

  • S.Q. Liew et al.

    Extraction and characterization of pectin from passion fruit peels

    Agric. Agric. Sci. Procedia

    (2014)
  • Y. Xu et al.

    Effects of ultrasound and/or heating on the extraction of pectin from

    J. Food Eng.

    (2014)
  • A. Palaniappan et al.

    Characterization of xylan from rice bran and finger millet seed coat for functional food applications

    J. Cereal Sci.

    (2017)
  • S. Banerjee et al.

    Hemicellulose based biorefinery from pineapple peel waste: xylan extraction and its conversion into xylooligosaccharides

    Food Bioprod. Process.

    (2019)
  • U. Ejaz et al.

    Cellulose extraction from methyltrioctylammonium chloride pretreated sugarcane bagasse and its application

    Int. J. Biol. Macromol.

    (2020)
  • M.A. Mahmud et al.

    Sugarcane bagasse - a source of cellulosic fiber for diverse applications

    Heliyon

    (2021)
  • R.G.P. Viera et al.

    Synthesis and characterization of methylcellulose from sugar cane bagasse cellulose

    Carbohydr. Polym.

    (2007)
  • G.R. Filho et al.

    Characterization of methylcellulose produced from sugar cane bagasse cellulose: crystallinity and thermal properties

    Polym. Degrad. Stab.

    (2007)
  • M.S. Sarwar et al.

    Preparation and characterization of PVA/nanocellulose/Ag nanocomposite films for antimicrobial food packaging

    Carbohydr. Polym.

    (2018)
  • M.C. Popescu et al.

    The influence of cellulose nanocrystals content on the water sorption properties of bio-based composite films

    Mater. Des.

    (2017)
  • B.D. Vogt et al.

    Moisture absorption into ultrathin hydrophilic polymer films on different substrate surfaces

    Polymer (Guildf.)

    (2005)
  • N. Cañigueral et al.

    Behavior of biocomposite materials from flax strands and starch-based biopolymer

    Chem. Eng. Sci.

    (2009)
  • M.A. Cerqueira et al.

    Effect of glycerol and corn oil on physicochemical properties of polysaccharide films - a comparative study

    Food Hydrocoll.

    (2012)
  • K. Saelee et al.

    Extraction and characterization of cellulose from sugarcane bagasse by using environmental friendly method

  • D. Klemm et al.

    Cellulose: fascinating biopolymer and sustainable raw material

    Angew. Chem.Int. Ed.

    (2005)
  • H. Ville et al.

    Nonappa, methylcellulose-cellulose nanocrystal composites for optomechanically tunable hydrogels and fibers

    Materials (Basel)

    (2021)
  • A. Sidana et al.

    Sugarcane bagasse: a potential medium for fungal cultures

    Chin.J. Biol.

    (2014)
  • J. Xu et al.

    Amylose/cellulose nanofiber composites for all-natural, fully biodegradable and flexible bioplastics

    Carbohydr. Polym.

    (2021)
  • M.S. Rahman et al.

    Conversion of lignocellulosic corn agro-waste into cellulose derivative and its potential application as pharmaceutical excipient

    Processes.

    (2020)
  • D.A.Bocchini Martins et al.

    Agroindustrial wastes as substrates for microbial enzymes production and source of sugar for bioethanol production

  • F.L. Ferreira et al.

    Sugarcane bagasse as a source of carbon for enzyme production by filamentous fungi1

    Hoehnea

    (2018)
  • Cited by (4)

    View full text