Textile waste cellulose nanofibrillated fibre has been reported with excellent strength reinforcement ability in other biopolymers. In this research cellulose nanofibrilated fibre (CNF) was isolated from the textile waste cotton fabrics with combined supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was used to enhance the polylactic acid/chitin (PLA/chitin) properties. The properties enhancement effect of the CNF was studied by characterising the PLA/chitin/CNF biocomposite for improved mechanical, thermal, and morphological properties. The tensile properties, impact strength, dynamic mechanical analysis, thermogravimetry analysis, scanning electron microscopy, and the PLA/chitin/CNF biocomposite wettability were studied. The result showed that the tensile strength, elongation, tensile modulus, and impact strength improved significantly with chitin and CNF compared with the neat PLA. Furthermore, the scanning electron microscopy SEM (Scanning Electron Microscopy) morphological images showed uniform distribution and dispersion of the three polymers in each other, which corroborate the improvement in mechanical properties. The biocomposite's water absorption increased more than the neat PLA, and the contact angle was reduced. The results of the ternary blend compared with PLA/chitin binary blend showed significant enhancement with CNF. This showed that the three polymers' combination resulted in a better material property than the binary blend.
This study aimed to produce polyhydroxyalkanoates (PHAs) from organic wastes by mixed bacterial cultures using anaerobic-aerobic fermentation systems. Palm oil mill effluent (POME) was used as an organic source, which was cultivated in a two-step-process of acidogenesis and acid polymerization. POME was operated in a continuous flow anaerobic reactor to access volatile fatty acids (VFAs) for PHAs production. During fermentation, VFA concentration was produced in the range of 5 to 8 g/L and the COD concentration reduced up to 80% from 65 g/L. The VFA from anaerobic fermentation was then utilised for PHA production using a mixed culture in availability of aerobic bioreactor. Production of PHAs was recorded high when using a high volume of substrates because of the higher VFA concentration. Even though the maximum PHA content was observed at only 40% of the cell dried weight (CDW), their production and performance are significant in mixed microbial culture.
Simultaneous Saccharification and Fermentation (SSF) is a process where microbes have to first excrete extracellular enzymes to break polymeric substrates such as starch or cellulose into edible nutrients, followed by in situ conversion of those nutrients into more valuable metabolites via fermentation. As such, SSF is very attractive as a one-pot synthesis method of biological products. However, due to the co-existence of multiple biochemical steps, modeling SSF faces two major challenges. The first is to capture the successive chain-end and/or random scission of the polymeric substrates over time, which determines the rate of generation of various fermentable substrates. The second is to incorporate the response of microbes, including their preferential substrate utilization, to such a complex broth. Each of the above-mentioned challenges has manifested itself in many related areas, and has been competently but separately attacked with two diametrically different tools, i.e., the Population Balance Modeling (PBM) and the Cybernetic Modeling (CM), respectively. To date, they have yet to be applied in unison on SSF resulting in a general inadequacy or haphazard approaches to examine the dynamics and interactions of depolymerization and fermentation. To overcome this unsatisfactory state of affairs, here, the general linkage between PBM and CM is established to model SSF. A notable feature is the flexible linkage, which allows the individual PBM and CM models to be independently modified to the desired levels of detail. A more general treatment of the secretion of extracellular enzyme is also proposed in the CM model. Through a case study on the growth of a recombinant Saccharomyces cerevisiae capable of excreting a chain-end scission enzyme (glucoamylase) on starch, the interlinked model calibrated using data from the literature (Nakamura et al., Biotechnol. Bioeng. 53:21-25, 1997), captured features not attainable by existing approaches. In particular, the effect of various enzymatic actions on the temporal evolution of the polymer distribution and how the microbes respond to the diverse polymeric environment can be studied through this framework.
To overcome drawbacks in the conventional chemical route to synthesize eugenyl benzoate, immobilized Rhizomucor miehei lipase (RML) as the biocatalyst was proposed. The RML conjugated to a hybrid support consisting of biopolymers, chitosan (CS) and chitin nanowhiskers (CNWs). 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDAC) was used as the crosslinker to bind the lipase. Immobilization of RML was the highest on crosslinked CS/CNWs which gave a protein loading of ∼8.12 mg/g, corresponding to specific and residual activity of 537 U/g and 137%, respectively. Fourier transform infrared spectroscopy, thermogravimetric analysis-differential thermogravimetry, field emission scanning electron and atomic force microscopy of RML-CS/CNWs revealed that RML was successfully attached to the surface of crosslinked CS/CNWs. Under an optimized condition, the highest yield of eugenyl benzoate (56.3%) was attained after 5 h using 3 mg/mL of RML-CS/CNWs with molar ratio of eugenol: benzoic acid of 3:1, as compared to only 47.3% for the free RML. Analyses of FTIR and NMR on purified eugenyl benzoate affirmed that the ester was successfully produced in the enzymatic esterification. Therefore, the use of the RML-CS/CNWs biocatalysts appears promising to afford good yields of eugenyl benzoate within a relatively shorter reaction time.
In recent years, the demand for a natural plant-based polymer with potential functions from plant sources has increased considerably. The main objective of the current study was to study the effect of chemical extraction conditions on the rheological and functional properties of the heteropolysaccharide/protein biopolymer from durian (Durio zibethinus) seed. The efficiency of different extraction conditions was determined by assessing the extraction yield, protein content, solubility, rheological properties and viscoelastic behavior of the natural polymer from durian seed. The present study revealed that the soaking process had a more significant (p < 0.05) effect than the decolorizing process on the rheological and functional properties of the natural polymer. The considerable changes in the rheological and functional properties of the natural polymer could be due to the significant (p < 0.05) effect of the chemical extraction variables on the protein fraction present in the molecular structure of the natural polymer from durian seed. The natural polymer from durian seed had a more elastic (or gel like) behavior compared to the viscous (liquid like) behavior at low frequency. The present study revealed that the natural heteropolysaccharide/protein polymer from durian seed had a relatively low solubility ranging from 9.1% to 36.0%. This might be due to the presence of impurities, insoluble matter and large particles present in the chemical structure of the natural polymer from durian seed.
Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films' modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.
New food packaging materials provide an attractive option for the advancement of nanomaterials. The poor thermal, mechanical, chemical, and physical properties of biopolymers and their inherent permeability to gases and vapor have increased this interest. Polymeric materials (matrix) in modern technologies require a filler, which can react/interact with the available matrix to provide a new formulation with improved packaging properties including oxygen permeability, moisture permeability, crystalline structure, barrier properties, morphology, thermal stability, optical properties, anti-microbial characteristics, and mechanical properties. The performance of nanocomposite films and packaging is dependent on the size of the nanofillers used and the uniformity of the nanoparticles (NPs) distribution and dispersion in the matrix. Advancement in nanocomposite technologies is expected to grow with the advent of sustainable, low price, environmentally friendly materials with an enhanced performance. The current review addresses advances in the biopolymeric nanocomposites as alternatives to petroleum plastics in the food packaging industry. It also provides a brief description of biopolymer nanocomposite films and gives general information about different metal NPs with an emphasis on their influence on the emerging characteristics of biodegradable films. The results of recent reports provide a better understanding of the influence of metal NPs in food packaging.
Petroleum based thermoplastics are widely used in a range of applications, particularly in packaging. However, their usage has resulted in soaring pollutant emissions. Thus, researchers have been driven to seek environmentally friendly alternative packaging materials which are recyclable as well as biodegradable. Due to the excellent mechanical properties of natural fibres, they have been extensively used to reinforce biopolymers to produce biodegradable composites. A detailed understanding of the properties of such composite materials is vital for assessing their applicability to various products. The present review discusses several functional properties related to packaging applications in order to explore the potential of bamboo fibre fabric-poly (lactic) acid composites for packaging applications. Physical properties, heat deflection temperature, impact resistance, recyclability and biodegradability are important functional properties of packaging materials. In this review, we will also comprehensively discuss the chronological events and applications of natural fibre biopolymer composites.
Chitosan, a prestigious versatile biopolymer, has recently received considerable attention as a promising biosorbent for recovering gold ions, mainly Au(III), from aqueous solutions, particularly in modified forms. Confirming the assertion, this paper provides an up-to-date overview of Au(III) recovery from aqueous solutions by raw (unmodified) and modified chitosan. A particular emphasis is placed on the raw chitosan and its synthesis from chitin, characteristics of raw chitosan and their effects on metal sorption, modifications of raw chitosan for Au(III) sorption, and characterization of raw chitosan before and after modifications for Au(III) sorption. Comparisons of the sorption (conditions, percentage, capacity, selectivity, isotherms, thermodynamics, kinetics, and mechanisms), desorption (agents and percentage), and reusable properties between raw and modified chitosan in Au(III) recovery from aqueous solutions are also outlined and discussed. The major challenges and future prospects towards the large-scale applications of modified chitosan in Au(III) recovery from aqueous solutions are also addressed.
Antimicrobial irradiated seaweed-neem biocomposite films were synthesized in this study. The storage functional properties of the films were investigated. Characterization of the prepared films was conducted using SEM, FT-IR, contact angle, and antimicrobial test. The macroscopic and microscopic including the analysis of the functional group and the gas chromatography-mass spectrometry test revealed the main active constituents present in the neem extract, which was used an essential component of the fabricated films. Neem leaves' extracts with 5% w/w concentration were incorporated into the matrix of seaweed biopolymer and the seaweed-neem bio-composite film were irradiated with different dosages of gamma radiation (0.5, 1, 1.5, and 2 kGy). The tensile, thermal, and the antimicrobial properties of the films were studied. The results revealed that the irradiated films exhibited improved functional properties compared to the control film at 1.5 kGy radiation dosage. The tensile strength, tensile modulus, and toughness exhibited by the films increased, while the elongation of the irradiated bio-composite film decreased compared to the control film. The morphology of the irradiated films demonstrated a smoother surface compared to the control and provided surface intermolecular interaction of the neem-seaweed matrix. The film indicated an optimum storage stability under ambient conditions and demonstrated no significant changes in the visual appearance. However, an increase in the moisture content was exhibited by the film, and the hydrophobic properties was retained until nine months of the storage period. The study of the films antimicrobial activities against Staphylococcus aureus (SA), and Bacillus subtilis (BS) indicated improved resistance to bacterial activities after the incorporation of neem leaves extract and gamma irradiation. The fabricated irradiated seaweed-neem bio-composite film could be used as an excellent sustainable packaging material due to its effective storage stability.
Considerable attention has been directed to nanoparticles based on gelatin biopolymer due to its numerous available active group sites for attaching target molecules and acting as a drug or nutraceutical delivery system aiming to improve the therapeutic effects and also to reduce the side effects of formulated drugs as gelatin is a natural biodegradable biocompatible polymer, nontoxic, readily available, cheap and is used in parental formulations. With mammalian gelatin (pig and cow) as the major source of gelatin production, alternatives are required due to sociocultural and health concerns to maintain halal status. This paper aims at reviewing fish skin gelatin from warm water species which can provide a potential alternative source of gelatin with almost the same rheological properties as mammalian gelatin and is a beneficial way to use fish waste such as skin, bones and fin which is generally discarded. The study also entails a lot of research being done in the field of nanoencapsulation of gelatin with various nutraceuticals as well as drug and gene therapy. There is an especially increasing interest in encapsulating biopeptides within gelatin nanoparticles in the functional food industry due to their role in preventing or delaying the onset of various diseases, food fortification, improvement of food quality, increase in shelf life, targeted peptide delivery and hence can be used as additives in food products. This review also attempts to provide an overview of the application of gelatin nanoparticles in nanoencapsulation in the food industry.
Xanthan integrated graphene oxide functionalized by titanium dioxide was successfully prepared through facile, eco-friendly and cost effective ice-templating technique. The three-dimensional (3D) graphene composite demonstrated relatively high temperature stability, chemical functionalities and porous sponge-like structure. The adsorption of lead was favored by high initial concentration and shaking speed at the operational solution pH. The process equilibrium and kinetic adhered to the Langmuir and pseudo-second-order correlations, respectively. The biomass integrated graphene composite showed maximum adsorption capacities ranging from 132.18 to 199.22 mg/g for 30-70 °C. Moreover, it was highly regenerable under mild conditions (0.1 M hydrochloric acid, 30 °C) and used repeatedly while retaining 84.78% of its initial adsorption capacity at the fifth adsorption-regeneration cycle. With comparatively high lead adsorption capacities, adequate recyclability and environmentally friendliness, the as-prepared 3D graphene composite has high application potential in heavy metal-wastewater separation for protection of the environment and human health.
This paper discusses the process technology to fabricate multilayer-Polydimethylsiloxane (PDMS) based microfluidic device for bio-particles concentration detection in Lab-on-chip system. The micro chamber and the fluidic channel were fabricated using standard photolithography and soft lithography process. Conventional method by pouring PDMS on a silicon wafer and peeling after curing in soft lithography produces unspecific layer thickness. In this work, a multilayer-PDMS method is proposed to produce a layer with specific and fixed thickness micron size after bonding that act as an optimum light path length for optimum light detection. This multilayer with precise thickness is required since the microfluidic is integrated with optical transducer. Another significant advantage of this method is to provide excellent bonding between multilayer-PDMS layer and biocompatible microfluidic channel. The detail fabrication process were illustrated through scanning electron microscopy (SEM) and discussed in this work. The optical signal responses obtained from the multilayer-PDMS microfluidic channel with integrated optical transducer were compared with those obtained with the microfluidic channel from a conventional method. As a result, both optical signal responses did not show significant differences in terms of dispersion of light propagation for both media.
The development of membrane technology from biopolymer for water filtration has received a great deal of attention from researchers and scientists, owing to the growing awareness of environmental protection. The present investigation is aimed at producing poly(D-lactic acid) (PDLA) membranes, incorporated with nanocrystalline cellulose (NCC) and cellulose nanowhisker (CNW) at different loadings of 1 wt.% (PDNC-I, PDNW-I) and 2 wt.% (PDNC-II PDNW-II). From morphological characterization, it was evident that the nanocellulose particles induced pore formation within structure of the membrane. Furthermore, the greater surface reactivity of CNW particles facilitates in enhancing the surface wettability of membranes due to increased hydrophilicity. In addition, both thermal and mechanical properties for all nanocellulose filled membranes under investigation demonstrated significant improvement, particularly for PDNW-I-based membranes, which showed improvement in both aspects. The membrane of PDNW-I presented water permeability of 41.92 L/m2h, when applied under a pressure range of 0.1-0.5 MPa. The investigation clearly demonstrates that CNWs-filled PDLA membranes fabricated for this investigation have a very high potential to be utilized for water filtration purpose in the future.
Globally, agro-industrial by products such as fruit waste has attained immense recognition to be used for the extraction of valuable functional ingredients. Pectin is naturally occurring biopolymer that is widely recognized in food industry as well as in biotechnology. Keeping in view, current research was conducted for extraction, characterization and utilization of grapefruit peel pectin from Duncan cultivar. The extracted pectin was characterized for different parameters that explored its role in value added products. Acid extraction was carried out and then pectin was characterized for equivalent weight, ash content and methoxyl content. With the addition of extracted pectin, jam was prepared and analysed for physicochemical analysis and sensory attributes. The maximum extraction (22.55%) was done from grapefruit peel at temperature-120°C with pH-1.5, while minimum extraction (0.41%) was obtained at temperature-120°C with pH-2. Moreover, adding pectin in jam formulation resulted in significant effect on texture of the final product. Conclusively, pectin holds a great potential to be extracted and utilized in fruit based products for best quality and value addition.
Over recent years, keratin has gained great popularity due to its exceptional biocompatible and biodegradable nature. It has shown promising results in various industries like poultry, textile, agriculture, cosmetics, and pharmaceutical. Keratin is a multipurpose biopolymer that has been used in the production of fibrous composites, and with necessary modifications, it can be developed into gels, films, nanoparticles, and microparticles. Its stability against enzymatic degradation and unique biocompatibility has found their way into biomedical applications and regenerative medicine. This review discusses the structure of keratin, its classification and its properties. It also covers various methods by which keratin is extracted like chemical hydrolysis, enzymatic and microbial treatment, dissolution in ionic liquids, microwave irradiation, steam explosion technique, and thermal hydrolysis or superheated process. Special emphasis is placed on its utilisation in the form of hydrogels, films, fibres, sponges, and scaffolds in various biotechnological and industrial sectors. The present review can be noteworthy for the researchers working on natural protein and related usage.
Cupriavidus sp. USMAA1020, a local isolate was able to biosynthesis poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer with various 4HB precursors as the sole carbon source. Manipulation of the culture conditions such as cell concentration, phosphate ratio and culture aeration significantly affected the synthesis of P(3HB-co-4HB) copolymer and 4HB composition. P(3HB-co-4HB) copolymer with 4HB compositions ranging from 23 to 75 mol% 4HB with various mechanical and thermal properties were successfully produced by varying the medium aeration. The physical and mechanical properties of P(3HB-co-4HB) copolymers were characterized by NMR spectroscopy, gel-permeation chromatography, tensile test, and differential scanning calorimetry. The number-average molecular weights (M (n)) of copolymers ranged from 260 x 10(3) to 590 x 10(3)Da, and the polydispersities (M (w)/M (n)) were between 1.8 and 3.0. Increases in the 4HB composition lowered the molecular weight of these copolymers. In addition, the increase in 4HB composition affected the randomness of copolymer, melting temperature (T (m)), glass transition temperature (T (g)), tensile strength, and elongation to break. Enzymatic degradation of P(3HB-co-4HB) films with an extracellular depolymerase from Ochrobactrum sp. DP5 showed that the degradation rate increased proportionally with time as the 4HB fraction increased from 17 to 50 mol% but were much lower with higher 4HB fraction. Degradation of P(3HB-co-4HB) films with lipase from Chromobacterium viscosum exhibited highest degradation rate at 75 mol% 4HB. The biocompatibility of P(3HB-co-4HB) copolymers were evaluated and these copolymers have been shown to support the growth and proliferation of fibroblast cells.
The contribution of microbial depolymerase has received much attention because of its potential in biopolymer degradation. In this study, the P(3HB) depolymerase enzyme of a newly isolated Burkholderia cepacia DP1 from soil in Penang, Malaysia, was optimized using response surface methodology (RSM). The factors affecting P(3HB) depolymerase enzyme production were studied using one-variable-at-a-time approach prior to optimization. Preliminary experiments revealed that the concentration of nitrogen source, concentration of carbon source, initial pH and incubation time were among the main factors influencing the enzyme productivity. An increase of 9.4 folds in enzyme production with an activity of 5.66 U/mL was obtained using optimal medium containing 0.028% N of di-ammonium hydrogen phosphate and 0.31% P(3HB-co-21%4HB) as carbon source at the initial pH of 6.8 for 38 h of incubation. Moreover, the RSM model showed great similarity between predicted and actual enzyme production indicating a successful model validation. This study warrants the ability of P(3HB) degradation by B. cepacia DP1 in producing higher enzyme activity as compared to other P(3HB) degraders being reported. Interestingly, the production of P(3HB) depolymerase was rarely reported within genus Burkholderia. Therefore, this is considered to be a new discovery in the field of P(3HB) depolymerase production.
Bovine gelatin is a biopolymer which has good potential to be used in encapsulating matrices for probiotic candidate Bifidobacterium pseudocatenulatum strain G4 (G4) because of its amphoteric nature characteristic. Beads were prepared by the extrusion method using genipin and sodium alginate as a cross-linking agent. The optimisation of bovine gelatin-genipin-sodium alginate combinations was carried out using face central composition design (FCCD) to investigate G4 beads' strength, before and after exposed to simulated gastric (SGF), intestinal fluids (SIF), and encapsulation yield. A result of ANOVA and the polynomial regression model revealed the combinations of all three factors have a significant effect (p < 0.05) on the bead strength. Meanwhile, for G4 encapsulation yield, only genipin showed less significant effect on the response. However, the use of this matrix remained due to the intermolecular cross-linking ability with bovine gelatin. Optimum compositions of bovine gelatin-genipin-sodium alginate were obtained at 11.21% (w/v), 1.96 mM, and 2.60% (w/v), respectively. A model was validated for accurate prediction of the response and showed no significant difference (p > 0.05) with experimental values.
Sustainable crop production for a rapidly growing human population is one of the current challenges faced by the agricultural sector. However, many of the chemical agents used in agriculture can be hazardous to humans, non-targeted organism and environment. Plant growth promoting rhizobacteria have demonstrated a role in promoting plant growth and health under various stress conditions including disease. Unfortunately, bacterial viability degrades due to temperature and other environmental factors (Bashan et al., Plant Soil 378: 1-33, 2014). Encapsulation of bacteria into core-shell biopolymers is one of the promising techniques to overcome the problem. This study deals with the encapsulation of Bacillus salmalaya 139SI using simple double coating biopolymer technique which consist of brown rice protein/alginate and 0·5% low molecular weight chitosan of pH 4 and 6. The influence of biopolymer to bacteria mass ratio and the chitosan pH on the encapsulation process, physic-chemical, morphology and bioactivity properties of encapsulated B. salmalaya 139SI have been studied systematically. Based on the analysis of physico-chemical, morphology and bioactivity properties, B. salmalaya 139S1 encapsulated using double coating encapsulation technology has promising viability pre- and postfreeze-drying with excellent encapsulation yields of 99·7 and 89·3% respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: The need of a simple yet effective way of encapsulating plant growth promoting rhizobacteria is crucial to further improve their benefits to global sustainable agriculture practice. Effective encapsulation allows for protection, controlled release and function of the micro-organism, as well as providing a longer shelf life for the product. This research report offers an innovative yet simple way of encapsulating using double coating technology with environmentally friendly biopolymers that could degrade and provide nutrients when in soil. Importantly, the bioactivity of the bacteria is maintained upon encapsulation.