Gluconate Research Articles

Whole-Genome Analysis of Novacetimonas cocois and the Effects of Carbon Sources on Synthesis of Bacterial Cellulose

Novacetimonas cocois WE7 (formally named Komagataeibacter cocois WE7) is a strain isolated from contaminated coconut milk, capable of producing bacterial cellulose (BC). We sequenced its genome to investigate why WE7 cannot synthesize BC from glucose efficiently. It contains about 3.5 Mb and six plasmid DNAs. N. cocois WE7 contains two bcs operons (bacterial cellulose operon, bcs I and bcs II); the absence of bcs III operons may lead to reduced BC production. From genome predictions, glucose, sucrose, fructose, maltose, and glycerol can be utilized to generate BC, with WE7 unable to metabolize carbohydrate carbon sources through the Embden–Meyerhof–Parnas (EMP) pathway, but rather through the Hexose Monophosphate Pathway (HMP) and tricarboxylic acid (TCA) pathways. It has a complete gluconic acid production pathway, suggesting that BC yield might be very low when glucose, maltose, and trehalose are used as carbon sources. This study represents the first genome analysis of N. cocois. This information is crucial for understanding BC production and regulation mechanisms in N. cocois and lays a foundation for constructing engineered strains tailored for diverse BC application purposes.

A multivalent polyphenol–metal-nanoplatform for cascade amplified chemo-chemodynamic therapy

Chemodynamic therapy (CDT), as an emerging therapeutic strategy, kills cancer cells by converting intracellular hydrogen peroxide (H2O2) into cytotoxic oxidizing hydroxyl radicals (⋅OH). However, the therapeutic efficiency of CDT is compromised due to the insufficient endogenous H2O2 and metal catalysts in tumor cells. The use of multivalent polyphenols with multiple hydroxyl functions provides a facile yet robust means for efficient CDT augmentation. For this purpose, we reported herein the construction of polyphenol–metal nanoparticles (NPs) via a phenol–metal coordination strategy. The uniqueness of this study is the preparation of only one polymer construct with multivalency that can afford various supramolecular interactions for simultaneous “one-pot” loading of different therapeutic species, i.e., doxorubicin (DOX), glucose oxidases (GOD), and Fe3+ and further co-self-assembly into a stabilized nanomedicine for cascade amplified chemo-chemodynamic therapy. Specifically, the tumor intracellular acidic pH-triggered DOX release could serve for chemotherapy as well as enhance the intracellular H2O2 level. Together with the extra H2O2 and gluconic acid produced by the GOD-triggered glucose consumption, DOX@POAD-Fe@GOD NPs promoted Fe3+participation in the Fe-mediated Fenton reaction for cascade amplified chemo-chemodynamic therapy. Notably, this formulation displayed a greater anti-tumor effect with a tumor inhibition ratio 1.6-fold higher than that of free DOX in a BALB/c mice model bearing 4T1 tumors. Overall, the multivalent polyphenol–metal nanoplatform developed herein integrates chemotherapy, starvation therapy, and CDT for synergistic enhanced anticancer efficiency, which shows great potential for clinical translations. Statement of significanceChemodynamic therapy (CDT) generally suffers from compromised therapeutic efficiency due to insufficient endogenous H2O2 and metal catalysts in tumor cells. To develop a facile yet robust strategy for efficient CDT augmentation, we reported herein construction of a multivalent polyphenol–metal nanoplatform, DOX@POAD-Fe@GOD nanoparticles (NPs) via a phenol–metal coordination strategy. This nanoplatform integrates multiple supramolecular dynamic interactions not only for simultaneously safe encapsulation of doxorubicin (DOX), Fe3+, and glucose oxidases (GOD), but also for cascade amplified chemo-chemodynamic therapy. Specifically, the intracellular acidic pH-triggered dissociation of DOX@POAD-Fe@GOD NPs promoted the release of Fe3+, DOX, and GOD for significantly increased ROS levels that can accelerate Fenton reactions for cascaded chemotherapy, starvation therapy, and CDT with amplified antitumor efficiency in vivo.

Gold mineralized “hybrid nanozyme bomb” for NIR-II triggered tumor effective permeation and cocktail therapy

Lung cancer is one of the most common malignant tumors with the fastest increase in the incidence rate and mortality. Even after maximum tumor resection assistance with a radiotherapy and chemotherapy combination, the recurrence of non-small cell lung cancer is still inevitable. In addition, low targeting efficiency and poor permeability of drug delivery systems strongly affect the therapeutic efficiency of anti-cancer drugs on non-small cell lung cancer. Here we designed a gemcitabine (GEM) loaded arginine-glycine-aspartic acid-cysteine (RGDc)-modified gold mineralization “hybrid nanozyme bomb” (RGTG) to overcome those obstacles. RGDc modification improved the active targeting of liposomes to the tumor tissues with the second near-infrared (NIR-II)-triggered gold-shell disruption and GEM release. The collapsed gold-shell particles with a smaller size could penetrate the tumor solid barrier and act as photothermal therapy (PTT) agents to improve PTT therapy and starvation therapy via generating gluconic acid and reactive oxygen species (ROS). Moreover, the resting reversal effect of gold particles on tumor fibroblasts can achieve accelerating tumor penetration of gold particles and GEM. Compared to monotherapy, RGTG showed significant improvement in tumor inhibition, with a tumor volume reduction of 83% compared to the control group, which provides a promising tumor treatment platform for non-small cell lung cancer (NSCLC).

The influence of Acetobacter pomorum bacteria on the developmental progression of Drosophila suzukii via gluconic acid secretion.

Insects are rich in various microorganisms, which play diverse roles in affecting host biology. Although most Drosophila species prefer rotten fruits, the agricultural pest Drosophila suzukii attacks ripening fruits before they are harvested. We have reported that the microbiota has positive and negative impacts on the agricultural pest D. suzukii on nutrient-poor and -rich diets, respectively. On nutrient-poor diets, microbes provide protein to facilitate larval development. But how they impede D. suzukii development on nutrient-rich diets is unknown. Here we report that Acetobacter pomorum (Apo), a commensal bacterium in many Drosophila species and rotting fruit, has several detrimental effects in D. suzukii. Feeding D. suzukii larvae nutrient-rich diets containing live Apo significantly delayed larval development and reduced the body weight of emerged adults. Apo induced larval immune responses and downregulated genes of digestion and juvenile hormone metabolism. Knockdown of these genes in germ-free larvae reproduced Apo-like weakened phenotypes. Apo was confirmed to secrete substantial amounts of gluconic acid. Adding gluconic acid to the D. suzukii larval diet hindered larval growth and decreased adult body weight. Moreover, the dose of gluconic acid that adversely affected D. suzukii did not negatively affect Drosophila melanogaster, suggesting that D. suzukii is less tolerant to acid than D. melanogaster. Taken together, these findings indicate that D. suzukii is negatively affected by gluconic acid, which may explain why it prefers ripening fruit over Apo-rich rotting fruit. These results show an insect's tolerance to microbes can influence its ecological niche.

Polymer-Assisted Coprecipitation Synthesized Zinc Oxide Nanoparticles and Their Uses for Green Chemical Synthesis via Photocatalytic Glucose Conversions.

Biomass conversions to chemicals via various conventional technologies require high energy consumption, high temperature, high pressure, or high system cost. Alternatively, photocatalysis is one of the greener technologies because it utilizes the energy from lamps or natural sunlight with catalysts to synthesize chemicals under mild conditions and room temperature. In this work, zinc oxide (ZnO) particles were successfully synthesized using polyvinylpyrrolidone as an additive in coprecipitation to control the size and protect the aggregation. The crystal structure of hexagonal wurtzite was found in the obtained nanoparticles. The photocatalytic activities of the obtained samples were evaluated for the production of high-value chemicals (gluconic acid, xylitol, arabinose, and formic acid) via the photocatalytic conversion of glucose under UV-A irradiation. The photocatalytic results indicated the relationship of defects (i.e., oxygen vacancies and zinc vacancies) with glucose conversions. From the ZnO nanoparticles calcined at various temperatures from 400 to 700 °C, the one calcined at 700 °C showed the highest glucose conversion of 21.5% with a high yield of carboxylic acid products (gluconic acid and formic acid). The gluconic acid showed the highest yield of 15% for 180 min, while the formic acid, arabinose, and xylitol presented the highest yields of 7, 1, and 0.5% for 180 min, respectively. Pure ZnO nanoparticles can convert glucose into value-added products without adding an acid or base in the reaction.

Nanozyme-enhanced glucose/O2 bio-photoelectrochemical system: Taking the challenge of earth diurnal variation

Achieving efficient and reasonable renewable energy utilization is crucial for sustainable socio-economy development. Herein, an ingenious glucose/O2 bio-photoelectrochemical system (BPECS) is developed to enhance glucose metabolism process for high-efficiency biofuels utilization. Capturing the intermittent nature of sunlight, glucose metabolism is divided into two-step reasonably. Under dark condition, bio-metabolism catalyzed by glucose oxidase (GOD), is conducted firstly to enrich gluconic acid and H2O2. Benefiting from specific electrocatalytic selectivity of BiVO4 photoanode and hemin cathode towards gluconic acid oxidation and H2O2 reduction, respectively, electro-matabolism occurs subsequently under light illumination. Moreover, profiting from prominently catalytic stability, a nanozyme-enhanced BPECS is constructed for the first time by integrating GOD-like Au nanoparticles, and a maximum power density of 139.17 μW cm−2 with open-circuit voltage of 0.62 V, is obtained. Such a BPECS provides a guiding significance for exploration of renewable energy sources and opens up a new path to expand nanozymes in extensive research fields.

DNA flexible chain modified MOFs as a versatile platform for chemoenzymatic cascade reactions in glucose catalysis

Glucose oxidase (GOD) is widely used in the pharmaceutical industry, fermentation products and glucose biosensors for its essential role in catalyzing the conversion of glucose to gluconic acid and hydrogen peroxide (H2O2). As H2O2 is the by-product and will have a toxic effect on glucose oxidase, so introducing another enzyme that could consume H2O2 to form an enzymatic cascade reaction is a practical solution. However, this decision will lead to extra expenses and complex condition optimization such as the specific mass ratio, temperature and pH to improve the activity, stability and recyclability. Herein, we describe a mild and versatile strategy by anchoring GOD on carboxyl-activated MOF (Cu-TCPP(Fe)) through DNA-directed immobilization (DDI) technology. Robust MOF nanosheets were utilized as not only the carrier for the immobilization of GOD, but also a peroxidase-like catalyst for the decomposition of H2O2 to reduce its harmful impacts. In this work, the immobilized GOD retained 55.78% of its initial activity after being used for 7 times. More than 60% of the immobilized enzyme's catalytic activity was still maintained after 96 h of being stored at 50 ℃. This study provides a new idea for preparing immobilized enzymes with enhanced stability, fast diffusion and high activity, which can be used in fields such as biocatalysis and biotechnology.

An effective method for the direct crystallization of xylonic acid from fermentation broth of agricultural residue hydrolysate

Xylose is the second most abundant sugar in nature and conversion of xylose to xylonic acid (XA) has become a research hotspot in recent years. Xylonic acid can be applied in the equivalent market niche of gluconic acid, due to their similar physical properties. XA bioproduction and application presents certainly a promising approach for xylose valorization in lignocellulose biorefinery, while the XA crystallization is so far still an unattainable goal. In this paper, an original method was proposed and experimentally investigated for the first time to get XA crystals from fermentation broth. In the XA crystallization, methanol was introduced as buffer-cum-solvent. The H2SO4 was dropwise added into the methanol solution dissolving potassium xylonate that is beforehand produced by fermentation. During H2SO4 blending with methanol, the strong and polar H2SO4 leads to XA diffusion and aggregation. Overall, 2.21 g of xylonic acid crystals was obtained per gram of 98% H2SO4 acidification. NMR detection showed that over 99% purity of XA crystals was finally obtained at the yields of 67.2% from xylonate. The integrated process could provide a practicable and effective technology for the high-qualify XA preparation from xylose derivations and lignocellulose biomass biorefinery.

Sustainable bioleaching of lithium-ion batteries for critical metal recovery: Process optimization through design of experiments and thermodynamic modeling

Recycling spent lithium-ion batteries (LIBs) could alleviate supply risks for critical metals and be less harmful to the environment compared to new production of metals from mining. Developing a cost-effective LIB bioleaching process could be a promising alternative to traditional energy-intensive recycling technologies. This study aimed to optimize bioleaching conditions for maximum economic competitiveness through design of experiments using iterative response surface methodology (RSM), assisted by thermodynamic modeling. The optimal condition was identified as 2.5% pulp density in 75 mM gluconic acid biolixiviant at 55°C for 30 h which could recover 57%–84% of nickel, 71%–86% of cobalt, and 100% of lithium and manganese, yielding a 17%–26% net profit margin. The recommended pulp density and acid concentrations, together with the observed metal solubilization, were supported by thermodynamic modeling predictions. Our study demonstrated that combining RSM with thermodynamic simulations could be a powerful tool for optimizing bioleaching conditions.

Uptake of Pu(IV) by hardened cement paste in the presence of gluconate at high and low ionic strengths

The uptake of Pu(IV) by hardened cement paste (HCP) at degradation state I was investigated in the absence and presence of gluconate (GLU). Furthermore, the influence of the ionic strength was examined in different background electrolytes. Artificial cement pore water (ACW, pH = 13) was used for low ionic strength (I = 0.3 M), and cement pore water based on the diluted caprock solution (ACW-VGL, pH = 12.5) was used for high ionic strength (I = 2.5 M). Sorption experiments were performed under an Ar atmosphere using HCP in the HCP/GLU binary system ([GLU]0 = 1 × 10−1–1 × 10−8 M) and the HCP/Pu(IV)/GLU ternary system ([239Pu(IV)]0 = 1 × 10−8 M, [GLU]0 = 1 × 10−2 M) with solid-to-liquid (S/L) ratios of 0.5–50 g L–1 within a contact time of 72 h. GLU sorbs strongly on HCP; a saturation of the sorption sites of HCP with GLU was observed at [GLU] ≥ 1 × 10−4 M at S/L = 5 g L–1. The effects of the order of addition of the components Pu(IV) and GLU on the sorption of Pu(IV) on HCP were investigated. In the absence of GLU, a quantitative uptake (S% ≥ 99%) of Pu(IV) by HCP was observed, independent of the ionic strength of the background electrolytes. In the presence of 1 × 10−2 M GLU, the sorption of Pu(IV) on HCP was significantly lower. For X-ray absorption fine structure (XAFS) measurements, powder samples with Pu ([239Pu(III)]0 = 5 × 10−6 M) sorbed on HCP (S/L = 2.5 g L–1) were prepared at pH ≈ 13 in ACW and ACW-VGL, respectively. One additional sample was prepared in the presence of GLU ([GLU]0 = 1 × 10−2 M) with ACW-VGL as the electrolyte for comparison. Pu LIII-edge X-ray absorption near-edge structure (XANES) spectra show that Pu is in the tetravalent oxidation state after being taken up by the HCP. The structural parameters obtained from extended X-ray absorption fine structure (EXAFS) analysis and comparison with literature indicate incorporation of Pu(IV) into the calcium-silicate-hydrate (C-S-H) phases of HCP. The different ionic strengths and the presence of GLU had no influence on the near-neighbor environment of Pu in HCP.

Comparison of structure and neuroprotective ability of low molecular weight galactomannans from Sesbania cannabina obtained by different extraction technologies.

Low-molecular-weight-galactomannan (LMW-GM) is an edible polysaccharide with various biological activities. However, it is used in the field of neuroprotection. In this study, two types of LMW-GMs from Sesbania cannabina were obtained by gluconic acid extraction (GA-LMW-GM) and enzymatic hydrolysis (GMOS). The structure of GA-LMW-GM and GMOS were identified using different nuclear magnetic resonance (NMR) techniques. The antioxidant and neuroprotective activities of GA-LMW-GM and GMOS were evaluated in vitro/vivo. The results showed that both GA-LMW-GM and GMOS possess good free radicals scavenging ability in vitro with IC50 values of 1.9mg/mL and 4.9mg/mL for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals 2.8mg/mL and 4.4mg/mL for O2•- radicals, respectively. However, GA-LMW-GM was more effective at scavenging reactive oxygen species (ROS) in vivo and protecting the fundamental growth (with a recovery capability of 62.5%) and locomotor functions (with recovery capability of 193.7%) of zebrafish with neurological damage induced by Bisphenol AF.

Periodontitis therapy with iron alginate and glucose oxidase based on the Fenton reaction

Periodontitis is a frequent chronic inflammatory disease brought on by bacterial infection in the biofilm that forms on the teeth. It can cause the gingival recession and tooth loss, gravely jeopardizing the oral health of people. Current therapies still suffer from issues like bleeding, pain, injured gums, limited treatment effectiveness, a lengthy treatment cycle, and bacterial resistance when using a combination of surgical intervention and antibiotic therapy. Herein, a simple one-step cross-linking process was used to create glucose oxidase (GOD) loaded upon iron alginate (FeAlg/GOD), which has a strong anti-biofilm activity, good biocompatibility, and was successfully used to treat periodontitis caused by biofilms. The results demonstrated that in the presence of a high glucose concentration in the gingival crevicular fluid, FeAlg/GOD could catalyze the conversion of glucose into gluconic acid and hydrogen peroxide. The produced hydrogen peroxide could convert Fe3+ to Fe2+ when it got to the deep periodontal pockets. Following that, the Fenton reaction was activated, producing large amounts of hydroxyl radical (OH). In conclusion, oral plaque biofilms were removed by the FeAlg/GOD. Additionally, successful in vivo treatment was accomplished in rat's experimental periodontitis models, as evidenced by a markedly reduced inflammatory response, decreased bone loss, and made healthier gum tissue. Overall, our biocompatible and antibacterial FeAlg/GOD study presents a novel strategy for effectively speeding periodontal tissue repair and eliminating oral pathogens to tackle the grave threat of biofilm-associated illnesses.

Systemic biochemical changes in pepper (Capsicum annuum L.) against Rhizoctonia solani by kale (Brassica oleracea var. acephala L.) green manure application

BackgroundIn the search for new alternatives to avoid the problems associated with the use of synthetic chemical fungicides in agriculture, the use of green manure (GrM) could help combat fungal diseases of crops, such as those produced by the necrotrophic pathogen Rhizoctonia solani. In the case of the use of Brassica tissues as GrM, it could have an elicitor capacity for systemic plant resistance.ResultsWe used kale leaves as a GrM and applied it to pepper plants infected with R. solani. The application of freeze-dried kale tissues to the roots of pepper plants produced a systemic activation of foliar defences via the salicylic acid (SA) and ethylene (ET) pathways, significantly reducing pathogen damage. In addition, this systemic response led to the accumulation of secondary defence metabolites, such as pipecolic acid, hydroxycoumarin and gluconic acid, in leaves. Remarkably, pepper plants treated with lyophilised kale GrM accumulated glucosinolates when infected with R. solani. We also confirmed that autoclaving removed part of the glucobrassicin (85%) and sinigrin (19%) content of the kale tissues.ConclusionsGrM kale tissues can activate systemic defences in bell pepper against foliar pathogens through SA/ET hormonal pathways, accumulating secondary defence metabolites.

Ultrasmall Bi/Cu Coordination Polymer Combined with Glucose Oxidase for Tumor Enhanced Chemodynamic Therapy by Starvation and Photothermal Treatment.

Multi-modal combination therapy for tumor is expected to have superior therapeutic effect compared with monotherapy. In this study, a super-small bismuth/copper-gallic acid coordination polymer nanoparticle (BCN) protected by polyvinylpyrrolidone is designed, which is co-encapsulated with glucose oxidase (GOX) by phospholipid to obtain nanoprobe BCGN@L. It shows that BCN has an average size of 1.8 ± 0.7nm, and photothermal conversion of BCGN@L is 31.35% for photothermal imaging and photothermal therapy (PTT). During the treatment process of 4T1 tumor-bearing nude mice, GOX catalyzes glucose in the tumor to generate gluconic acid and hydrogen peroxide (H2 O2 ), which reacts with copper ions (Cu2+ ) to produce toxic hydroxyl radicals (•OH) for chemodynamic therapy (CDT) and new fresh oxygen (O2 ) to supply to GOX for further catalysis, preventing tumor hypoxia. These reactions increase glucose depletion for starvation therapy , decrease heat shock protein expression, and enhance tumor sensitivity to low-temperature PTT. The in vitro and in vivo results demonstrate that the combination of CDT with other treatments produces excellent tumor growth inhibition. Blood biochemistry and histology analysis suggests that the nanoprobe has negligible toxicity. All the positive results reveal that the nanoprobe can be a promising approach for incorporation into multi-modal anticancer therapy.

Looking for Novel Natural Gels to Improve Cleaning Methods for Bronze Leachates on Marble.

Marble is one of the materials most susceptible to copper leaching, resulting in easily identifiable turquoise stains on the marble. This problem is particularly relevant when we are talking about marble structures of heritage value. For this reason, conservators look for cleaning materials that are specific to the structure to be treated without damaging the original surface. Materials such as agar have been studied for a long time. Agar creates a controlled water release system that adapts to the needs of conservators who seek the greatest possible cleanliness without damaging the material to be treated. To improve the cleaning, chelating agents such as EDTA are added to the agar composition. However, the microbiological growth and the damage it produces to the original material are disadvantages to take into account. In order to solve these problems, other natural materials with cleaning potential such as kudzu and konjac gels were studied in combination with other chelating agents such as citrate, oxalate, and gluconic acid. For the characterization and evaluation of copper cleaning, various analytical techniques were used, including Raman spectroscopy, colorimetry, X-ray fluorescence (XRF), and inductively coupled plasma mass spectrometry (ICP-MS). In this study, both konjac and kudzu emerged as promising alternatives to agar, revealing distinctive features such as simplified preparation methods and inherent antimicrobial properties. The EDTA chelator was found to be the most harmful for marble surfaces, as it extracted a greater amount of calcium from the marble during application of the gels doped with it. Citrate and gluconic acid have been identified as a promising substitute to prepare doped gels for the removal of copper stains. These compounds exhibit comparable or potentially superior cleaning capabilities than EDTA, with no negative side effects.

Stiffness‐Switchable, Biocatalytic pH‐Responsive DNA‐Functionalized Polyacrylamide Cryogels and their Mechanical Applications

AbstractThe large‐pore interconnected channels in cryogels, allow convectional flow and rapid mass‐transport of solute constituents between the solution and cryogel polymer framework, as compared to slower, diffusionally‐controlled mass‐transport in small‐pore hydrogels. These features are applied to develop enzyme‐loaded polyacrylamide (pAAm) cryogels, and glucose oxidase (GOx)‐loaded pH‐responsive DNA‐based pAAm cryogels, revealing enhanced biocatalytic transformations, enhanced temporal stiffness changes, and mechanical bending functions, as compared to analog hydrogels. DNA‐based pAAm cryogel/hydrogel matrices, revealing pH‐switchable stiffness properties through reversible reconfiguration of DNA‐bridging units into i‐motif structures, are introduced. Enhanced switchable stiffness changes of DNA‐based pAAm cryogels, as compared to analog hydrogels, are demonstrated upon subjecting the cryogel/hydrogel matrices to auxiliary pH‐changes, or by integration of GOx into the frameworks, and driving pH‐changes through GOx‐catalyzed aerobic oxidation of glucose to gluconic acid. Enhanced stiffness changes of pAAm cryogels represent a major advance to control the mechanical properties of cryogels and are attributed to the convectionally‐controlled mass‐transport in the cryogel matrices. Moreover, bilayer constructs consisting of poly‐N‐isopropylacrylamide (pNIPAM) cryogels and pH‐responsive DNA‐based pAAm cryogel or hydrogel structures are constructed. Enhanced pH/glucose triggered mechanical bending rates of the pNIPAM cryogel/pAAm cryogel or pNIPAM cryogel/GOx‐loaded pAAm cryogel, as compared to analog pNIPAM cryogel/pAAm hydrogel frameworks are demonstrated.

Production of bacterial cellulose by Komagataeibacter intermedius from spent sulfite liquor

This study explores the use of spent sulfite liquor, a byproduct of pulp mills, as a sustainable carbon source for bacterial cellulose production. Komagataeibacter intermedius successfully grew on the sulfite-based medium after pretreatment and addition of media components. Comparisons with standard medium and a standard media with the addition of lignosulfonates using Komagataeibacter xylinus were conducted. The results revealed that for both bacteria sulfite medium outperformed the other two, with a significantly higher cellulose production of 5.68 g L−1 compared to 1.86 g L−1 and 2.17 g L−1 for Komagataeibacter intermedius. Inhibition of the gluconic acid production pathway on sulfite medium medium led to 13 % increased cellulose yield. The celluloses produced on sulfite-based medium exhibited, with 375.8 kg mol−1, higher molecular masses and similar structures to standard media celluloses with only 209.6 kg mol−1. This is highlighting the potential of pretreated spent sulfite liquor to enhance bacterial cellulose properties as a favorable carbon source.

Biodegradable nanotherapeutic with simultaneously GSH depletion and H2O2 supplying for enhanced synergistic chemotherapy/chemodynamic therapy

Chemodynamic therapy (CDT) has been exploited as an emerging therapeutic modality for cancer treatment. However, insufficient intracellular H2O2 levels and ultrahigh glutathione (GSH) in the tumor microenvironment (TME) severely restrict CDT efficacy. To address these concerns, in this work, a self-reinforcing biodegradable nanotherapeutic was developed to modulate the TME to amplify CDT. The nanotherapeutic (GOD-FeCaP@TPZ, abbreviated GFCT) was fabricated through a mild one-step biomineralization process using the enzyme catalyst glucose oxidase (GOD) as a template to form biodegradable iron-doped calcium phosphate nanoparticles, followed by the loading of the prodrug tirapazamine (TPZ). When GFCT decomposes and releases Fe3+ in the acidic TME, the delivered GOD can effectively catalyze the oxidization of glucose to enhance the subsequent Fenton-like reaction by promoting intracellular acidity (via the production of gluconic acid) and improving the generation of H2O2. Moreover, the released iron constantly depletes GSH by self-cyclic valence alterations in Fe(III) and Fe(II) and then triggers H2O2 to produce •OH through an Fe(II)-mediated Fenton-like reaction. Moreover, the elevated level of hypoxia induced by GOD-mediated glucose oxidization can activate the prodrug TPZ for effective chemotherapy, thus achieving remarkable synergistic therapeutic outcomes. This work provides another paradigm to augment antitumor efficacy via modulation of the TME.

Ulva rigida Valorization into Poly(3-hydroxybutyrate), Organic Acids and Functional Ingredients.

Halomonas elongata 1H9T is a moderate halophilic strain able to produce poly(3-hydroxybutyrate) (P(3HB)), a biodegradable plastic, and gluconic acid, a valuable organic acid with wide industrial applications. In this work, the green alga Ulva rigida was used as platform to produce cultivation substrates for microbial conversion as well as functional ingredients, targeting its full valorization. The liquor obtained by autohydrolysis presented the highest concentration of oligosaccharides and protein, being an interesting feedstock to produce functional ingredients. The acid and/or enzymatic hydrolysis liquors are adequate as substrates for microbial processes. Shake flask assays with H. elongata revealed that the N-rich liquor produced after acidic treatment was the best suited for cell growth while the N-poor liquor produced by the enzymatic treatment of acid-pretreated algae residues produced the highest P(3HB) titers of 4.4 g/L. These hydrolysates were used in fed-batch cultivations as carbon and protein sources for the co-production of gluconic acid and polymer achieving titers of 123.2 g/L and 7.2 g/L, respectively. Besides gluconic acid, the Krebs cycle intermediate 2-oxoglutaric acid, also called alpha-ketoglutaric acid (KGA), was produced. Therefore, the co-production of P(3HB) and acids may be of considerable interest as an algal biorefinery valorization strategy.

Purification of Galacto-oligosaccharide (GOS) by fermentation with Kluyveromyces lactis and Interaction between GOS and casein under simulated acidic fermentation conditions.

In the enzymatic synthesis of galacto-oligosaccharide (GOS), the primary by-products include glucose, galactose and unreacted lactose. This This study was aimed to provide a method to to purify GOS by yeat fermentation and explore the interaction between GOS and CAS with a view for expanding the prospects of GOS application in the food industry. The crude GOS(25.70g/L) was purified in this study using the fermentation method with Kluyveromyces lactis CICC 1773. Optimal conditions for purification with the yeast were 75g/L of the yeast inoculation rate and 50g/L of the initial crude GOS concentration for 12h of incubation. After removing ethanol produced by yeast by low-temperature distillation, GOS content could reach 90.17%. A study of the interaction between GOS and casein (CAS) in a simulated acidic fermentation system by D-(+)-gluconic acid δ-lactone (GDL) showed that the GOS/CAS complexes with higher GOS concentrations, e.g., 4% and 6% (w/v), was more viscoelastic with higher water-holding capacity, but decreased hardness, elasticity, and cohesiveness at 6% (w/v) of GOS. The addition of GOS to CAS suspension significantly caused (p<0.05) decreased particle sizes of the formed GOS/CAS complexes, and the suspension system became more stable. FT-IR spectra confirmed the existence of different forms of molecular interactions between CAS and GOS, e.g., hydrogen bonding and hydrophobic interaction, and the change of secondary structure after CAS binding to GOS.