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Synthesis of Pullulan
Published in Shakeel Ahmed, Aisverya Soundararajan, Pullulan, 2020
Pullulan is an extracellular, linear homopolysaccharide consisting of maltotriose and maltotetraose with α-(1→6) and α-(1→4) linkages. The molecular weight of pullulan having the molecular formula (C6H10O5)n is in the range of 10–3000 kDa [1, 12, 14, 21]. This unique structure makes pullulan highly soluble in water and flexible. Pullulan is nontoxic, nonmutagenic, noncarcinogenic, biodegradable, and edible [9, 24]. Pullulan has been successfully synthesized for a few decades under certain conditions such as time duration, pH, and phosphate concentration from the culture broth/(fungal strain) of Aureobasidium pullulans (for example Aureobasidium pullulans, Tremella mesenterica, Cytaria harioti, Cytaria darwinii, Cryphonectria parasitica, Teloschites flavicans, Rhodototula bacarum, and Aureobasidium pullulans). The synthesis of other polysaccharide varieties, similar to pullulan, has been done by other microbes [2, 22, 25, 28]. It has been well established that the regularly repeating unit of pullulan is a maltotriose trimer (produced extracellularly by A. pullulans) α-(1→4)Glup- α-(1→4)Glup- α-(1→6)Glup-. However, other repeating units in pullulan, tetramer or maltotetraose α-(1→4)Glup- α-(1→4)Glup- α-(1→4)Glup- α-(1→6)Glup-, may be present in the pullulan polymeric chain. But the maximum extent of maltotetraose subunits has been found to be only 7% [7].
Sources of Natural Polymers from Microorganisms with Green Nanoparticles
Published in Satya Eswari Jujjavarapu, Krishna Mohan Poluri, Green Polymeric Nanocomposites, 2020
K. Chandrasekhar, Satya Eswari Jujjavarapu, Prasun Kumar, Gopalakrishnan Kumar, Potla Durthi Chandrasai, Enamala Manoj Kumar, Murthy Chavali
Regarding food industry applications, pullulan is widely used as a thickening agent, a stabilizing agent, and also as a prebiotic agent. Regarding biomedical applications, pullulan is used in gene delivery, tissue engineering, wound healing, and diagnostic applications (An et al., 2017; Cheng et al., 2011; K.R & V, 2017; Singh et al., 2016; Tabasum et al., 2018; Wang et al., 2015). Regarding pharmaceutical applications, pullulan is widely employed in capsule manufacturing and drug delivery processes. To overcome a few limitations, this biopolymer can also be used together with supplementary biopolymers (An et al., 2017; Rovera et al., 2018). A few examples are pullulan–soy protein blend (for higher adhesion to the surface of the food), pullulan–caseinate blend (for high thermal stability), pullulan–whey protein blend (for oxygen permeability, water vapor permeability, and appearance), pullulan–hydroxypropyl methylcellulose blend (for thermos-mechanical properties), pullulan–sodium alginate blend (for thermos-mechanical properties), pullulan–gelatin mixture (for mechanical and oxygen permeability) etc. Even though pullulan has many attractive applications in different fields, it has not been effectively as exploited as it deserves. At the moment very few commercial products are available that relate to pullulan biopolymers. One of the limiting factors for this is its cost of production.
Modeling and Fermentatation Aspects of Pullulan Production from Jaggery
Published in Megh R Goyal, Sustainable Biological Systems for Agriculture, 2018
Pullulan is a water soluble random coil glucan, consisting of regularly repeating copolymer of maltotriose trimer {1→6)-a-D-glucopyranosyl- (1→4)-a-D-glucopyranosyl-(1→4)-a-D-glucopyranosyl-(1→n}. This regular alteration of a-(1→4) and a-(1→6) bonds results in two distinctive properties of structural flexibility and enhanced solubility along with adhesive film/fiber forming, oxygen impermeability properties.60 Pullulan has been considered as “Generally Regarded As Safe” (GRAS) status by United States Food and Drug Administration (USFDA) (Fig. 7.1). Pullulan is being widely used as an edible film, binding agent, flocculating agent, as plasma expander, entitles this polysaccharide as “wonder biopolymer.” Pullulan production has been stable with major applications in food and pharma industries for number of years, but nowadays pullulan is being tested for capsule formation, edible packaging and environmental bioremediation.
Industrial production and applications of α/β linear and branched glucans
Published in Indian Chemical Engineer, 2021
Geetha Venkatachalam, Senthilkumar Arumugam, Mukesh Doble
Different types of α and β glucans and their applications are explained in Tables 1 and 2. Molecular weight of water insoluble glucans like curdlan and cellulose vary from 5 × 104–106 respectively. The molecular weight of water-soluble glucan such as salecan is ∼ 2 × 104, 5 × 105 for β-(1,3)-(1,6) glucan and ∼ 3000–5000 Da for cyclosophorans. So their applications vary widely. In particular they have been widely used and tested as therapeutic agents for their anti-inflammatory, immune potentiating, antiviral, antitumour and drug delivery properties. Antioxidant properties of some glucans are exploited in cosmetic formulations as anti-ageing agents [3]. α-glucans have been used as prebiotics for active functioning of gastrointestine. Dextran with molecular weight of 106–109 Da [4] have been used as texturing, viscosifying, gelling and emulsifying agents in food industry. It also improves the quality of bread by increasing the volume, texture and crumbliness [42]. Bacterial glucans are also used as materials in construction, electrical, agriculture and paper industries. Amylopectin is used as storage supplement, food, paper, textile and pharmaceutical products. Pullulan is widely used in silicone composite, blood plasma substitute, tensioactive agent and thickener. The less industrially important glucans which are produced by microbial sources are nigeran, elsinan, isolichenan, pseudonigeran, mutan, alternan and reuteran have not found any industrial applications
Optimization and characterization of pullulan production by a newly isolated high-yielding strain Aureobasidium melanogenum
Published in Preparative Biochemistry and Biotechnology, 2019
Guoqiang Chen, Youshuang Zhu, Ge Zhang, Haobao Liu, Yuxi Wei, Pinggui Wang, Fan Wang, Mo Xian, Haiying Xiang, Haibo Zhang
Pullulan is a water-soluble, unbranched homopolysaccharide mainly produced by Aureobasidium pullulans as an extracellular polysaccharide. It is mainly composed of repeating maltotriose units linked by α-(1→6) glucosidic linkages and the regular alternation is connected by α-(1→4) glucosidic linkages,[1,2] resulting in two distinctive properties of structural flexibility and enhanced solubility, which make it good raw materials to form fibers, adhesive properties, compression moldings, and oxygen-impermeable films.[3] Pullulan is also an economically important EPS, which is increasingly applied as a food component, environmental clean-up agent, adhesive, blood plasma substitute, and cosmetic additive.[4–8] The average molecular weight (MW) of pullulan ranges from 1.5 × 104 to 1.0 × 107 Da.[9] Recent research has shown that modified pullulan derivatives are potential candidates in medical and environmental remediation, and the demand for pullulan with specific molecular weight is increasing.[10,11]
Immunological response of polysaccharide nanogel-incorporating PEG hydrogels in an in vivo diabetic model
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Tugba Bal, Ismail Can Karaoglu, Fusun Sevval Murat, Esra Yalcin, Yoshihiro Sasaki, Kazunari Akiyoshi, Seda Kizilel
Hydrogel nanoparticles, referred as nanogels, are either physically or chemically crosslinked polymer networks with sizes less than 100 nm in diameter. Chemically crosslinked nanogels are formed by covalent bonds whereas physically crosslinked nanogels are established by non-covalent bonds such as electrostatic and hydrophobic interactions [17]. To achieve physical crosslinking, self-assembly method based on hydrophobic interactions can be used and it is an effective approach to synthesize nanogels [18]. Polymer systems containing both hydrophobic and hydrophilic groups in their structure are promising due to the simultaneous employment of non-covalent pi stackings and solubility in aqueous media [19]. Pullulan is a hydrophilic polysaccharide produced from the fungal fermentation of starch. Being biodegradable, non-toxic, non-immunogenic and FDA-approved, pullulan is a commonly used natural polymer in fields such as pharmaceutical, cosmetics and biomedical [20,21]. Moreover, pullulan has a good adhesive property, and it is reported to enhance MSC retention on injured cartilage tissue by providing a reparative environment [22]. Repeating groups of pullulan consist of maltotriose units which are suitable for functionalization with various molecules [23]. Among these molecules, functionalization of pullulan with cholesterol have attracted great attention in recent decades for the synthesis of nano and microstructures [24–28]. Cholesterol-bearing and acryloyl modified pullulan (CHPOA) nanogels are composed of hydrophilic structures of pullulan and hydrophobic cholesteryl groups. In aqueous media, aforementioned hydrophobic moieties of CHPOA are responsible for physical crosslinking [29]. Additionally, CHPOA nanogels have been reported to lack stimulatory molecules, which makes them immunologically inert [16,30]. Therefore, they have attracted attention to be tested in clinics. For instance, as a part of cancer vaccine, these nanoparticles were utilized to deliver NY-ESO-1 that evokes and facilitates T-cell response [31]. In a calvarial defect model, CHPOA nanogels were shown to enhance osteoprogenitor cell infiltration by releasing fibroblast growth factor-18 and bone morphogenic protein-2, resulting in fast recovery [32].