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Fulltext Nanobiocatalyst advancements and bioprocessing applications

Misson M, Zhang H, Jin B

J R Soc Interface, 2015 Jan 06;12(102):20140891.
PMID: 25392397 DOI: 10.1098/rsif.2014.0891

The nanobiocatalyst (NBC) is an emerging innovation that synergistically integrates advanced nanotechnology with biotechnology and promises exciting advantages for improving enzyme activity, stability, capability and engineering performances in bioprocessing applications. NBCs are fabricated by immobilizing enzymes with functional nanomaterials as enzyme carriers or containers. In this paper, we review the recent developments of novel nanocarriers/nanocontainers with advanced hierarchical porous structures for retaining enzymes, such as nanofibres (NFs), mesoporous nanocarriers and nanocages. Strategies for immobilizing enzymes onto nanocarriers made from polymers, silicas, carbons and metals by physical adsorption, covalent binding, cross-linking or specific ligand spacers are discussed. The resulting NBCs are critically evaluated in terms of their bioprocessing performances. Excellent performances are demonstrated through enhanced NBC catalytic activity and stability due to conformational changes upon immobilization and localized nanoenvironments, and NBC reutilization by assembling magnetic nanoparticles into NBCs to defray the high operational costs associated with enzyme production and nanocarrier synthesis. We also highlight several challenges associated with the NBC-driven bioprocess applications, including the maturation of large-scale nanocarrier synthesis, design and development of bioreactors to accommodate NBCs, and long-term operations of NBCs. We suggest these challenges are to be addressed through joint collaboration of chemists, engineers and material scientists. Finally, we have demonstrated the great potential of NBCs in manufacturing bioprocesses in the near future through successful laboratory trials of NBCs in carbohydrate hydrolysis, biofuel production and biotransformation.
Enhancing enzyme stability and metabolic functional ability of β-galactosidase through functionalized polymer nanofiber immobilization

Misson M, Jin B, Chen B, Zhang H

Bioprocess Biosyst Eng, 2015 Oct;38(10):1915-23.
PMID: 26104537 DOI: 10.1007/s00449-015-1432-5

A functionalized polystyrene nanofiber (PSNF) immobilized β-galactosidase assembly (PSNF-Gal) was synthesized as a nanobiocatalyst aiming to enhance the biocatalyst stability and functional ability. The PSNF fabricated by electrospinning was functionalized through a chemical oxidation method for enzyme binding. The bioengineering performance of the enzyme carriers was further evaluated for bioconversion of lactose to galacto-oligosaccharides (GOS). The modified PSNF-Gal demonstrated distinguished performances to preserve the same activity as the free β-galactosidase at the optimum pH of 7.0, and to enhance the enzyme stability of PSNF-Gal in an alkaline condition up to pH 10. The PSNF assembly demonstrated improved thermal stability from 37 to 60 °C. The nanobiocatalyst was able to retain 30 % of its initial activity after ninth operation cycles comparing to four cycles with the unmodified counterpart. In contrast with free β-galactosidase, the modified PSNF-Gal enhanced the GOS yield from 14 to 28 %. These findings show the chemically modified PSNF-based nanobiocatalyst may be pertinent for various enzyme-catalysed bioprocessing applications.
Dual-response quadratic model for optimisation of electricity generation and chlorophenol degradation by electro-degradative Bacillus subtilis in microbial fuel cell system

Hassan H, Jin B, Dai S

Environ Technol, 2021 Apr 01.
PMID: 33749543 DOI: 10.1080/09593330.2021.1907451

The interactions within microbial, chemical and electronic elements in microbial fuel cell (MFC) system can be crucial for its bio-electrochemical activities and overall performance. Therefore, this study explored polynomial models by response surface methodology (RSM) to better understand interactions among anode pH, cathode pH and inoculum size for optimising MFC system for generation of electricity and degradation of 2,4-dichlorophenol. A statistical central composite design by RSM was used to develop the quadratic model designs. The optimised parameters were determined and evaluated by statistical results and the best MFC systematic outcomes in terms of current generation and chlorophenol degradation. Statistical results revealed that the optimum current density of 106 mA/m2 could be achieved at anode pH 7.5, cathode pH 6.3-6.6 and 21-28% for inoculum size. Anode-cathode pHs interaction was found to positively influence the current generation through extracellular electron transfer mechanism. The phenolic degradation was found to have lower response using these three parameter interactions. Only inoculum size-cathode pH interaction appeared to be significant where the optimum predicted phenolic degradation could be attained at pH 7.6 for cathode pH and 29.6% for inoculum size.
Dendrimer-like nanoparticles based β-galactosidase assembly for enhancing its selectivity toward transgalactosylation

Misson M, Du X, Jin B, Zhang H

Enzyme Microb Technol, 2016 Mar;84:68-77.
PMID: 26827776 DOI: 10.1016/j.enzmictec.2015.12.008

Functional nanomaterials have been pursued to assemble nanobiocatalysts since they can provide unique hierarchical nanostructures and localized nanoenvironments for enhancing enzyme specificity, stability and selectivity. Functionalized dendrimer-like hierarchically porous silica nanoparticles (HPSNs) was fabricated for assembling β-galactosidase nanobiocatalysts for bioconversion of lactose to galacto-oligosaccharides (GOS). The nanocarrier was functionalized with amino (NH2) and carboxyl (COOH) groups to facilitate enzyme binding, benchmarking with non-functionalized HPSNs. Successful conjugation of the functional groups was confirmed by FTIR, TGA and zeta potential analysis. HPSNs-NH2 showed 1.8-fold and 1.1-fold higher β-galactosidase adsorption than HPSNs-COOH and HPSNs carriers, respectively, with the highest enzyme adsorption capacity of 328mg/g nanocarrier at an initial enzyme concentration of 8mg/ml. The HPSNs-NH2 and β-galactosidase assembly (HPSNs-NH2-Gal) demonstrated to maintain the highest activity at all tested enzyme concentrations and exhibited activity up to 10 continuous cycles. Importantly, HPSNs-NH2-Gal was simply recycled through centrifugation, overcoming the challenging problems of separating the nanocarrier from the reaction medium. HPSNs-NH2-Gal had distinguished catalytic reaction profiles by favoring transgalactosylation, enhancing GOS production of up to 122g/l in comparison with 56g/l by free β-galactosidase. Furthermore, it generated up to 46g/l GOS at a lower initial lactose concentration while the free counterpart had negligible GOS production as hydrolysis was overwhelmingly dominant in the reaction system. Our research findings show the amino-functionalized HPSNs can selectively promote the enzyme activity of β-galactosidase for transgalactosylation, which is beneficial for GOS production.
Manipulation of nanofiber-based β-galactosidase nanoenvironment for enhancement of galacto-oligosaccharide production

Misson M, Dai S, Jin B, Chen BH, Zhang H

J Biotechnol, 2016 Mar 20;222:56-64.
PMID: 26876609 DOI: 10.1016/j.jbiotec.2016.02.014

The nanoenvironment of nanobiocatalysts, such as local hydrophobicity, pH and charge density, plays a significant role in optimizing the enzymatic selectivity and specificity. In this study, Kluyveromyces lactis β-galactosidase (Gal) was assembled onto polystyrene nanofibers (PSNFs) to form PSNF-Gal nanobiocatalysts. We proposed that local hydrophobicity on the nanofiber surface could expel water molecules so that the transgalactosylation would be preferable over hydrolysis during the bioconversion of lactose, thus improve the galacto-oligosaccharides (GOS) yield. PSNFs were fabricated by electro-spinning and the operational parameters were optimized to obtain the nanofibers with uniform size and ordered alignment. The resulting nanofibers were functionalized for enzyme immobilization through a chemical oxidation method. The functionalized PSNF improved the enzyme adsorption capacity up to 3100mg/g nanofiber as well as enhanced the enzyme stability with 80% of its original activity. Importantly, the functionalized PSNF-Gal significantly improved the GOS yield and the production rate was up to 110g/l/h in comparison with 37g/l/h by free β-galactosidase. Our research findings demonstrate that the localized nanoenvironment of the PSNF-Gal nanobiocatalysts favour transgalactosylation over hydrolysis in lactose bioconversion.
Network Topology Optimization for Alignment Programming of a Dynamic Liquid Crystalline Organo-Gel

Jin B, Zhu Z, Wong TW, Chen G

ACS Macro Lett, 2023 Nov 21;12(11):1486-1490.
PMID: 37874195 DOI: 10.1021/acsmacrolett.3c00512

Liquid crystalline elastomers (LCEs) exhibit muscle-like actuation upon an external stimulus. To control this, various alignment programming strategies have been developed over the past decades. Among them, force-directed solvent evaporation, namely, that the alignment depends on the applied external force during solvent evaporation, is appreciated for its universality in material design and versatility in attainable actuations. Here, we investigate the influence of network topology on the alignment programming of a liquid crystalline (LC) organo-gel via varying feeding ratios of the monomers. As a result, distinct self-supporting actuations can be repeatedly introduced into a topology-optimized LC organo-gel. Beyond this, the bond exchange reaction of the embedded ester groups can be activated upon heating, which enables alignment manipulation based on dynamic network reconfiguration after drying. The availability of inviting two distinct programming strategies into one LCE network allows us to regulate the LCE alignment at both the gel and dried states, offering ample room to diversify actuation manners. Our design principle shall be adopted by other dynamic LCE systems owing to its maneuverability.
Antipyretic and antitumor effects of a purified polysaccharide from aerial parts of Tetrastigma hemsleyanum

Zhu B, Qian C, Zhou F, Guo J, Chen N, Gao C, et al.

J Ethnopharmacol, 2020 May 10;253:112663.
PMID: 32045682 DOI: 10.1016/j.jep.2020.112663

ETHNOPHARMACOLOGICAL RELEVANCE: Tetrastigma hemsleyanum Diels et Gilg (Sanyeqing) is traditionally used as a folk medicine for the treatments of inflammation, high fever, hepatitis and cancer, and can improve the immune function of the patient. It belongs to the family of Vitaceae, and is mainly distributed in southeast China (Yunnan province) and can be found in India (Andaman Islands), Myanmar, Thailand, Vietnam, Malaysia and Indonesia in the valleys with 1100-1300 m above the sea level.
AIM OF THE STUDY: The present study aimed to characterize the chemical properties of a purified polysaccharide extracted from the aerial part of Tetrastigma hemsleyanum (SYQP) and investigate its antipyretic and antitumor effects in mice models.
MATERIALS AND METHODS: Water-soluble crude polysaccharides from the aerial parts of Tetrastigma hemsleyanum were extracted and fractionated by DEAE and gel permeation chromatography. Homogeneity, molecular weight, monosaccharide composition, and FTIR analysis were performed to characterize the SYQP. Antipyretic effect of SYQP was examined using Brewer's yeast induced hyperthermia test. Antitumor effect was investigated using H22 tumor bearing mice. The serum cytokines were determined to evaluated the biological activities of SYQP.
RESULTS: SYQP was composed of galacturonic acid (GalA), glucose (Glc), mannose (Man), arabinose (Ara), galactose (Gal), and rhamnose (Rha) with a molar ratio of 11.3:7.1:2.5:1.0:0.9:0.5 and it had an average molecular weight of 66.2 kDa. The oral administration of SYQP at 200 and 400 mg/kg could markedly suppress the hyperthermia of mice induced by Brewer's yeast and decrease the production of cytokines especially prostaglandin E2 (PGE2) in the serum of mice. SYQP inhibited the growth of H22 tumor in mice with inhibitory rate of 39.9% at the administration dose of 200 mg/kg and increased the production of cytokines such as tumor necrosis factor-alpha (TNF-a) and interferon γ (IFN-γ). Experimental results showed that the preventive administration of SYQP before lipopolysaccharide (LPS) reduced the high cytokine levels such as IL-6, IL-10 and IFN-γ, indicating that SYQP might act as a competitor with LPS to interact with toll like receptor 4 (TLR4), which further regulated the secretion of cytokines.
CONCLUSION: The anti-inflammatory and antitumor activities of SYQP might be related to its regulation of host immune function by controlling the secretion of cytokines.
How culture influences patient preferences for patient-centered care with their doctors

Sheeran N, Jones L, Pines R, Jin B, Pamoso A, Eigeland J, et al.

J Commun Healthc, 2023 Jul;16(2):186-196.
PMID: 37401877 DOI: 10.1080/17538068.2022.2095098

BACKGROUND: Patient-centered care (PCC) is the prevailing model of care globally. However, most research on PCC has been conducted in Westernized countries or has focused on only two facets of PCC: decision-making and information exchange. Our study examined how culture influences patients' preferences for five facets of PCC, including communication, decision-making, empathy, individualized focus, and relationship.
METHODS: Participants (N = 2071) from Hong Kong, the Philippines, Australia, and the U.S.A. completed an online survey assessing their preferences for exchange of information, autonomy in decision-making, expression and validation of their emotions, focus on them as an individual, and the doctor-patient relationship.
RESULTS: Participants from all four countries had similar preferences for empathy and shared decision-making. For other facets of PCC, participants in the Philippines and Australia expressed somewhat similar preferences, as did those in the U.S.A. and Hong Kong, challenging East-West stereotypes. Participants in the Philippines placed greater value on relationships, whereas Australians valued more autonomy. Participants in Hong Kong more commonly preferred doctor-directed care, with less importance placed on the relationship. Responses from U.S.A. participants were surprising, as they ranked the need for individualized care and two-way flow of information as least important.
CONCLUSIONS: Empathy, information exchange, and shared decision-making are values shared across countries, while preferences for how the information is shared, and the importance of the doctor-patient relationship differ.
Fulltext Chronic hydatid cyst in malaysia: a rare occurence

Suria Hayati MP, Boon Teck Eugene C, Jan Jin B, Mohd Rose I

Malays J Med Sci, 2015 Jan-Feb;22(1):79-83.
PMID: 25892954 MyJurnal

Hydatid cysts are not endemic in Malaysia and are rarely seen. We hereby report a case of hydatid cyst of the liver in a 55-year-old Chinese-Australian lady who presented with a calcified liver cyst and negative hydatid serology. A liver segmentectomy was performed and revealed a well-circumscribed, calcified liver cyst containing only creamy whitish material without the typical daughter cyst. A histological examination revealed different layers of the cyst wall and the presence of loose, calcified scolices without a daughter cyst. The case highlights the importance of considering hydatid cyst in the differential diagnosis of liver cyst even in non-endemic areas, as the ease of travelling and migration allows the condition to be seen outside the endemic region.