<Emphasis Type="Italic">Hypericum japonicum:</Emphasis> a Double-Headed Sword to Combat Vector Control and Cancer

Weissella cibaria RBA12 produced a maximum of 9 mg/ml dextran (with 90% efficiency) using shake flask culture under the optimized concentration of medium components viz. 2% (w/v) of each sucrose, yeast extract, and K₂HPO₄ after incubation at optimized conditions of 20 °C and 180 rpm for 24 h. The optimized medium and conditions were used for scale-up of dextran production from Weissella cibaria RBA12 in 2.5-l working volume under batch fermentation in a bioreactor that yielded a maximum of 9.3 mg/ml dextran (with 93% efficiency) at 14 h. After 14 h, dextran produced was utilized by the bacterium till 18 h in its stationary phase under sucrose depleted conditions. Dextran utilization was further studied by fed-batch fermentation using sucrose feed. Dextran on production under fed-batch fermentation in bioreactor gave 35.8 mg/ml after 32 h. In fed-batch mode, there was no decrease in dextran concentration as observed in the batch mode. This showed that the utilization of dextran by Weissella cibaria RBA12 is initiated when there is sucrose depletion and therefore the presence of sucrose can possibly overcome the dextran hydrolysis. This is the first report of utilization of dextran, post-sucrose depletion by Weissella sp. studied in bioreactor.     

Optimization of Levan Production by Cold-Active <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> ANT 179 and Fructooligosaccharide Synthesis by Its Levansucrase

Fructooligosaccharides (FOS) and levan attract much attention due to a wide range of applications in food technology and pharmaceutical and cosmetic industry. Bacillus licheniformis ANT 179, isolated from Antarctica soil, produced levansucrase and levan in a medium containing sucrose as carbon substrate. In this study, characterization of levansucrase and production of short-chain FOS and levan were investigated. Temperature and pH optimum of the enzyme were found to be 60 °C and pH 6.0, respectively. The optimization of fermentation conditions for levan production using sugarcane juice by response surface methodology (RSM) was carried out. Central composite rotatable design was used to study the main and the interactive effects of medium components: sugarcane juice and casein peptone concentration on levan production by the bacterium. The optimized medium with sugarcane juice at 20 % (v/v) and casein peptone at 2 % (w/v) was found to be optimal at an initial pH of 7.0 and incubation temperature of 35 °C for 48 h. Under these conditions, the maximum levan concentration was 50.25 g/L on wet weight basis and 16.35 g/L on dry weight basis. The produced inulin type FOS (kestose and neokestose) and levan were characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analysis. The study revealed that the levansucrase could form FOS from sucrose. The locally available low-cost substrate such as sugarcane juice in the form of a renewable substrate is proposed to be suitable even for scale-up production of enzyme and FOS for industrial applications. The levan and FOS synthesized by the bacterium are suitable for food applications and biomedical uses as the bacterium has GRAS status and devoid of endotoxin as compared to other Gram-negative bacteria.     

Efficient Production of Prebiotic Gluco-oligosaccharides in Orange Juice Using Immobilized and Co-immobilized Dextransucrase

Dextransucrase from Leuconostoc mesenteroides NRRL B-512F was subjected to immobilization and co-immobilization with dextranase from Chaetomium erraticum. Immobilization has enhanced the operational and storage stability of dextransucrase. Two hundred milligrammes (2.4 IU/mg) of alginate beads (immobilized and co-immobilized) were found to be optimum for the production of gluco-oligosaccharides (GOS) in orange juice with a high degree of polymerization. The pulp of the orange juice did not interfere in the reaction. In the batch process, co-immobilized dextransucrase (41 g/L) produced a significantly higher amount of GOS than immobilized dextransucrase (37 g/L). Alginate entrapment enhanced the thermal stability of dextransucrase for up to 3 days in orange juice at 30 °C. The production of GOS in semi-continuous process was 39 g/L in co-immobilized dextransucrase and 33 g/L in immobilized dextransucrase. Thus, immobilization technology offers a great scope in terms of reusability and efficient production of a value added functional health drink.     

Immobilization and Characterization of <Emphasis Type="Italic">E. gracilis</Emphasis> Extract with Enriched Laminaribiose Phosphorylase Activity for Bienzymatic Production of Laminaribiose

Immobilization methods and carriers were screened for immobilization of Euglena gracilis extract with laminaribiose phosphorylase activity. The extract was successfully immobilized on three different carriers via covalent linkage. Suitable immobilization carriers were Sepabeads EC-EP/S and ECR 8209M with epoxy groups and ECR 8309M with amino groups as functional units. Immobilization on Sepabeads EC-EP/S resulted in highest retained activity (65%). The immobilizates were characterized for pH, temperature, and buffer molarity preferences. The immobilized enzyme lost 48% of its activity when used seven times. Together with sucrose phosphorylase, laminaribiose phosphorylase was successfully applied for bienzymatic production of laminaribiose from sucrose and glucose with a final laminaribiose concentration of 14.3 ± 2.1 g/L (20% yield).     

Enhanced Bioethanol Production from Potato Peel Waste Via Consolidated Bioprocessing with Statistically Optimized Medium

In this study, an extensive screening was undertaken to isolate some amylolytic microorganisms capable of producing bioethanol from starchy biomass through Consolidated Bioprocessing (CBP). A total of 28 amylolytic microorganisms were isolated, from which 5 isolates were selected based on high α-amylase and glucoamylase activities and identified as Candida wangnamkhiaoensis, Hyphopichia pseudoburtonii (2 isolates), Wickerhamia sp., and Streptomyces drozdowiczii based on 26S rDNA and 16S rDNA sequencing. Wickerhamia sp. showed the highest ethanol production (30.4 g/L) with fermentation yield of 0.3 g ethanol/g starch. Then, a low cost starchy waste, potato peel waste (PPW) was used as a carbon source to produce ethanol by Wickerhamia sp. Finally, in order to obtain maximum ethanol production from PPW, a fermentation medium was statistically designed. The effect of various medium ingredients was evaluated initially by Plackett-Burman design (PBD), where malt extracts, tryptone, and KH₂PO₄ showed significantly positive effect (p value < 0.05). Using Response Surface Modeling (RSM), 40 g/L (dry basis) PPW and 25 g/L malt extract were found optimum and yielded 21.7 g/L ethanol. This study strongly suggests Wickerhamia sp. as a promising candidate for bioethanol production from starchy biomass, in particular, PPW through CBP.     

Production of Mycophenolic Acid by <Emphasis Type="Italic">Penicillium brevicompactum</Emphasis> Using Solid State Fermentation

Solid-state fermentation using the microfungus Penicillium brevicompactum for the production of mycophenolic acid is reported in this paper. Of the initial substrates tested (whole wheat, cracked wheat, long grain Basmati rice, and short grain Parmal rice), Parmal rice proved to be the best. Under initial conditions, using steamed Parmal rice with 80% (w/w) initial moisture content, a maximum mycophenolic acid concentration of 3.4 g/kg substrate was achieved in 12 days of fermentation at 25 °C. The above substrate was supplemented with the following additional nutrients (g/L packed substrate): glucose 40.0, peptone 54.0, KH₂PO₄ 8.0, MgSO4?7H₂O 2.0, glycine 7.0, and methionine 1.65 (initial pH 5.0). A small amount of a specified trace element solution was also added. The final mycophenolic acid concentration was increased to nearly 4 g/kg substrate by replacing glucose with molasses. Replacing Parmal rice with rice bran as substrate further improved the mycophenolic acid production to nearly 4.5 g/kg substrate.     

Enhancing <Emphasis Type="SmallCaps">l</Emphasis>-Lysine Production of Beet Molasses by Engineered <Emphasis Type="Italic">Escherichia coli</Emphasis> Using an In Situ Pretreatment Method

Reducing the viscosity of molasses environmentally and selectively removing the harmful ingredients for microbes are the keys to promoting the bioavailability of molasses. A simple and environmental in situ pretreatment method integrating surfactants and alkali was developed to reduce the viscosity of molasses prior to l-lysine production using Escherichia coli ZY0217. Adding activated carbon and modified orange peel based on the in situ pretreatment process effectively removed pigments and excessive zinc in the molasses and also significantly increased the cell growth and l-lysine yield from E. coli ZY0217. The experimental results showed that a mixture of secondary alkane sulfonate, an anionic surfactant, and HodagCB-6, a non-ionic surfactant, effectively reduced the viscosity of the molasses more so than any single surfactant. When the surfactant mixture was added at a concentration of 0.04 g/L to the molasses, the ω value was 0.4, and when ammonia was added at 0.6 %, the lowest viscosity of 705 mPa?·?s was obtained. Further, 91.5 % of the color and 86.68 % of the original levels of zinc were removed using an activated carbon and modified orange peel treatment on the molasses with the lowest viscosity, which further promoted cell growth and l-lysine production. In the fed-batch cultivation process, the l-lysine concentration achieved using a constant-speed feeding strategy was 45.89 g/L, with an l-lysine yield of 27.18 %, whereas the l-lysine yield from untreated molasses was only 10.13 %. The increase in l-lysine yield was related to the reduced viscosity and the detoxification of the molasses. Lastly, the pretreatment was found to significantly enhance the conversion of sugars in the molasses to l-lysine.     

Efficient <Emphasis Type="Italic">Candida rugosa</Emphasis> lipase immobilization on Maghnite clay and application for the production of (<Emphasis Type="Italic">1R</Emphasis>)-(−)-Menthyl acetate

This work focused on the identification of natural, economical, and efficient supports for immobilization of Candida rugosa lipase (CRL) to catalyze the resolution of (±)-menthol. To this purpose, CRL has been immobilized on natural montmorillonite from Algeria (Maghnite-H), ion-exchange resins (Amberjet^®1200-H and Amberjet^®4200-Cl), and diatomaceous earth (Celite^®545). After a preliminary screening of supports, the immobilization of CRL led to a markedly improved enantioselectivity. Excellent enantioselectivity (E ≥ 134) was achieved by the four supported lipases (E = 68 for free enzyme). Compared to the three other supports tested, higher enantioselectivity was observed with Maghnite-H used as immobilization matrix. In this work, the effects of solvent, reaction time, and temperature, on the conversion as well as on enantioselectivity were investigated. The maximum of conversion (% C = 43%) with high enantiomeric excess of products (eep > 99) was obtained when the reaction is catalyzed by CRL immobilized on Maghnite-H at 30 °C for 24 h, and using toluene as selected solvent. Immobilized CRL on Maghnite-H exhibited good thermostability over a wide temperature range (30–90 °C) compared to the free one. These results suggest that CRL immobilized on Maghnite-H has good potential as biocatalyst for the production of (1R)-(?)-menthyl acetate.     

Acetone–Butanol–Ethanol Production from Waste Seaweed Collected from Gwangalli Beach,Busan, Korea,Based on pH-Controlled and Sequential Fermentation Using Two Strains

The optimal conditions for acetone–butanol–ethanol (ABE) production were evaluated using waste seaweed from Gwangalli Beach, Busan, Korea. The waste seaweed had a fiber and carbohydrate, content of 48.34%; these are the main resources for ABE production. The optimal conditions for obtaining monosaccharides based on hyper thermal (HT) acid hydrolysis of waste seaweed were slurry contents of 8%, sulfuric acid concentration of 138 mM, and treatment time of 10 min. Enzymatic saccharification was performed using 16 unit/mL Viscozyme L, which showed the highest affinity (K_m?=?1.81 g/L). After pretreatment, 34.0 g/L monosaccharides were obtained. ABE fermentation was performed with single and sequential fermentation of Clostridium acetobutylicum and Clostridium tyrobutyricum; this was controlled for pH. A maximum ABE concentration of 12.5 g/L with Y_ABE 0.37 was achieved using sequential fermentation with C. tyrobutyricum and C. acetobutylicum. Efficient ABE production from waste seaweed performed using pH-controlled culture broth and sequential cell culture.     

Improved Eu(III) immobilization by <Emphasis Type="Italic">Cladosporium sphaerospermum</Emphasis> induced by low-temperature plasma

To increase the bioaccumulation of Eu(III), low temperature plasma as a method of mutagenesis was introduced to mutate Cladosporium sphaerospermum (C. sphaerospermum). Mycelia doses, pH, and ionic strength obviously affected the Eu(III) immobilization on mycelia. The maximum immobilization capacities of Eu(III) on mutated C. sphaerospermum was 278.8 mg/g at pH 6.5, which was approximately three times than that of raw C. sphaerospermum. Before and after Eu(III) loaded mycelia were analyzed by XPS and FTIR, and intracellular structures of mycelia changed obviously under Eu(III) stress by TEM analysis. The results suggested that low temperature plasma could be utilized as a valuable treatment technology to improve fungi for the removal and immobilization of radionuclides in the environment.     

Application of Physicochemical Treatment Allows Reutilization of <Emphasis Type="Italic">Arthrospira platensis</Emphasis> Exhausted Medium

Since cultivations of Arthrospira platensis have a high water demand, it is necessary to develop treatment methods for reusing the exhausted medium that may prevent environmental problems and obtaining useful biomass. The exhausted Schlösser medium obtained from A. platensis batch cultivation in bench-scale mini-tanks was treated by varying concentrations of different coagulants, ferric chloride (6, 10, and 14 mg L^?1) or ferric sulfate (15, 25, and 35 mg L^?1) and powdered activated carbon (PAC, 30 and 50 mg L^?1). Such treated effluent was restored with NaNO₃ and reused in new cultivations of A. platensis performed in Erlenmeyer flasks. Reusing media through the cultivation of A. platensis showed satisfactory results, particularly in the medium treated with ferric chloride and PAC. The maximum cell concentration obtained in the flasks was 1093 mg L^?1, which corresponded to the medium treated with ferric chloride (6 mg L^?1) and PAC (30 mg L^?1). This cellular growth was higher than in the medium treated with ferric sulfate and PAC, in which values of maximum cell concentration did not exceed 796 mg L^?1. The cultures in the media after treatment did not modify the biomass composition. Thus, combined coagulation/adsorption processes, commonly used in water treatment processes, can be efficient and viable for treating exhausted medium of A. platensis, allowing the production of such biomass with the reduction of production cost and saving water.     

Polyhydroxybutyrate (PHB) Synthesis by <Emphasis Type="Italic">Spirulina</Emphasis> sp. LEB 18 Using Biopolymer Extraction Waste

The reuse of waste as well as the production of biodegradable compounds has for years been the object of studies and of global interest as a way to reduce the environmental impact generated by unsustainable exploratory processes. The conversion of linear processes into cyclical processes has environmental and economic advantages, reducing waste deposition and reducing costs. The objective of this work was to use biopolymer extraction waste in the cultivation of Spirulina sp. LEB 18, for the cyclic process of polyhydroxybutyrate (PHB) synthesis. Concentrations of 10, 15, 20, 25, and 30% (v/v) of biopolymer extraction waste were tested. For comparison, two assays were used without addition of waste, Zarrouk (SZ) and modified Zarrouk (ZM), with reduction of nitrogen. The assays were carried out in triplicate and evaluated for the production of microalgal biomass and PHB. The tests with addition of waste presented a biomass production statistically equal to ZM (0.79 g L^?1) (p?<?0.1). The production of PHB in the assay containing 25% of waste was higher when compared to the other cultivations, obtaining 10.6% (w/w) of biopolymer. From the results obtained, it is affirmed that the use of PHB extraction waste in the microalgal cultivation, aiming at the synthesis of biopolymers, can occur in a cyclic process, reducing process costs and the deposition of waste, thus favoring the preservation of the environment.     

A Multivariate Approach to Evaluate Biomass Production,Biochemical Composition and Stress Compounds of <Emphasis Type="Italic">Spirulina platensis</Emphasis> Cultivated in Wastewater

The study was performed to investigate the effects of using cow effluent for the cultivation of Spirulina platensis on its biomass production and cell physiology. S. platensis was cultivated in three different cow effluents (CE) used as cultivation medium during 15 days. CE was prepared using dry cow manures, and it was further modified with supplement of NaNO₃ (CEN) and NaNO₃ + NaCl (CENS). High nitrate value stimulated chlorophyll-a and total protein content of the cyanobacterium and also biomass production in standards medium (SM) and CEN media. Total carbohydrate content of S. platensis grown in CE media was found to be higher (p < 0.05) than that of SM. Productions of biomass and biochemical compounds by the cyanobacterium grown on the CE and SM media were evaluated by using multivariate approach. Conductivity, oxidation reduction potential (ORP), salinity, pH, and TDS played important role (p < 0.01) in the biochemical composition. As an effective explanatory factor, ORP had a significant positive correlation with H₂O₂, whereas negatively correlated with chlorophyll-α, biomass production, filament length, and proline. Canonical correspondence analysis proposed that biochemical compounds of S. platensis were not only affected by salinity and nutrition of media but also by pH and ORP. The present study indicated that CEN as a low cost model medium had high potential for the production of biomass by S. platensis with high protein content.     

Co-production of Fructooligosaccharides and Levan by Levansucrase from <Emphasis Type="Italic">Bacillus subtilis</Emphasis> natto with Potential Application in the Food Industry

Fructooligosaccharides and levan have a wide range of applications in the food industry due to their physiological and functional properties. The enzymatic synthesis of these molecules exhibits great advantages when compared with microbial fermentation. In this study, the production of levansucrase from Bacillus subtilis natto and its utilization in fructooligosaccharides and levan syntheses using different reaction conditions were described. The best condition for levansucrase production was 420.7 g L^?1 of sucrose at pH 7.0, which reached 23.9 U ml^?1 of transfructosylation activity. In a bioreactor, the highest production of fructooligosaccharides was 41.3 g L^?1 using a medium containing 350 g L^?1 sucrose at 35 °C for 36 h. The enzymatic synthesis of levan resulted in 86.9 g L^?1 when conditions similar to those used for fructooligosaccharides synthesis were applied. These results indicate that the levansucrase from B. subtilis natto could be applied for the co-production of fructooligosaccharides and levan, which are biomolecules that have health benefits and are used successfully in the food industry.     

On <Emphasis Type="Italic">Trans</Emphasis>-Resveratrol in Aqueous Solutions

A thermodynamic study on aqueous solutions of trans-Resveratrol (3,5,4′-trihydroxy-trans-stilbene) at 25.00 ± 0.02 °C, in 0.5 mol·dm^?3 NaCl, has been conducted. The protolysis equilibria and the complex formation between trans-Resveratrol and a metal(II), namely Mn²⁺ and Cu²⁺, have been investigated. The experimental method consists of potentiometric, spectrophotometric (absorption and emission) acid–base titrations. The pH range investigated is 2.5 ≤ pH ≤ 13 for the binary system, while for the ternary system it is 2.5 ≤ pH ≤ 6. The results of the graphical and numerical methods adopted indicate, for all the systems investigated, the formation of a predominant Me(II)–trans-Resveratrol mononuclear complex. UV–Vis absorption spectra and desorption/ionization time of flight mass spectra show the occurrence of hydrolytic species exhibiting a higher molecular weight than the Resveratrol molecule, becoming more evident as the pH and the time increased. Moreover, high performance liquid chromatography analysis and infrared spectroscopy of aqueous cis/trans-Resveratrol solutions upon excitation at 300 nm have highlighted a highly fluorescent compound, with absorption maximum at 250 nm, and a blue shift in the fluorescence emission that have not previously been reported.     

High Cell Density Process for Constitutive Production of a Recombinant Phytase in Thermotolerant Methylotrophic Yeast <Emphasis Type="Italic">Ogataea thermomethanolica</Emphasis> Using Table Sugar as Carbon Source

The yeast Ogataea thermomethanolica has recently emerged as a potential host for heterologous protein expression at elevated temperature. To evaluate the feasibility of O. thermomethanolica as heterologous host in large-scale fermentation, constitutive production of fungal phytase was investigated in fed-batch fermentation. The effect of different temperatures, substrate feeding strategies, and carbon sources on phytase production was investigated. It was found that O. thermomethanolica can grow in the temperature up to 40 °C and optimal at 34 °C. However, the maximum phytase production was observed at 30 °C and slightly decreased at 34 °C. The DOT stat control was the most efficient feeding strategy to obtain high cell density and avoid by-product formation. The table sugar can be used as an alternative substrate for phytase production in O. thermomethanolica. The highest phytase activity (134 U/mL) was obtained from table sugar at 34 °C which was 20-fold higher than batch culture (5.7 U/mL). At a higher cultivation temperature of 38 °C, table sugar can be used as a low-cost substrate for the production of phytase which was expressed with an acceptable yield (85 U/mL). Lastly, the results from this study reveal the industrial favorable benefits of employing O. thermomethanolica as a host for heterologous protein production.     

Bamboo (<Emphasis Type="Italic">Phyllostachys pubescens</Emphasis>) as a Natural Support for Neutral Protease Immobilization

Lignin polymers in bamboo (Phyllostachys pubescens) were decomposed into polyphenols at high temperatures and oxidized for the introduction of quinone groups from peroxidase extracted from bamboo shoots and catalysis of UV. According to the results of FT-IR spectra analysis, neutral proteases (NPs) can be immobilized on the oxidized lignin by covalent bonding formed by amine group and quinone group. The optimum condition for the immobilization of NPs on the bamboo bar was obtained at pH 7.0, 40 °C, and duration of 4 h; the amount of immobilized enzyme was up to 5 mg g^?1 bamboo bar. The optimal pH for both free NP (FNP) and INP was approximately 7.0, and the maximum activity of INP was determined at 60 °C, whereas FNP presented maximum activity at 50 °C. The K_m values of INP and FNP were determined as 0.773 and 0.843 mg ml^?1, respectively; INP showed a lower K_m value and V_max, than FNP, which demonstrated that INP presented higher affinity to substrate. Compared to FNP, INP showed broader thermal and storage stability under the same trial condition. With respect to cost, INP presented considerable recycling efficiency for up to six consecutive cycles.     

Quercetin Glucoside Production by Engineered <Emphasis Type="Italic">Escherichia coli</Emphasis>

Escherichia coli strains expressing the O-glucosyltransferases UGT73B3 or UGT84B1 were compared for the production of glucosides from quercetin supplied into a defined medium. The formation of quercetin-3-glucoside (Q3G) by UGT73B3 showed a maximum at 33 °C, while the formation of quercetin-7-glucoside by UGT84B1 increased with increasing temperature to 37 °C. The highest concentrations of Q3G were attained by strains having a deletion in the pgi gene-coding phosphoglucose isomerase, which effectively blocked the entry of glucose-6P into the Embden–Meyerhof–Parnas pathway. Formation of Q3G was improved in 1-L controlled bioreactors compared to shake flask cultures, a result attributed to the greater oxygen transfer rate in bioreactors. Under batch conditions with 30 g/L glucose as the sole carbon source, E. coli MEC367 (MG1655 pgi) expressing UGT73B3 generated 3.9 g/L Q3G in 56 h.     

Physical and Covalent Immobilization of <Emphasis Type="Italic">Lipase</Emphasis> onto Amine Groups Bearing Thiol-Ene Photocured Coatings

In this study, amine groups containing thiol-ene photocurable coating material for lipase immobilization were prepared. Lipase (EC 3.1.1.3) from Candida rugosa was immobilized onto the photocured coatings by physical adsorption and glutaraldehyde-activated covalent bonding methods, respectively. The catalytic efficiency of the immobilized and free enzymes was determined for the hydrolysis of p-nitrophenyl palmitate and also for the synthesis of p-nitrophenyl linoleate. The storage stability and the reusability of the immobilized enzyme and the effect of temperature and pH on the catalytic activities were also investigated. The optimum pH for free lipase and physically immobilized lipase was determined as 7.0, while it was found as 7.5 for the covalent immobilization. After immobilization, the optimum temperature increased from 37 °C (free lipase) to 50–55 °C. In the end of 15 repeated cycles, covalently bounded enzyme retained 60 and 70 % of its initial activities for hydrolytic and synthetic assays, respectively. While the physically bounded enzyme retained only 56 % of its hydrolytic activity and 67 % of its synthetic activity in the same cycle period. In the case of hydrolysis V _max values slightly decreased after immobilization. For synthetic assay, the V _max value for the covalently immobilized lipase was found as same as free lipase while it decreased dramatically for the physically immobilized lipase. Physically immobilized enzyme was found to be superior over covalent bonding in terms of enzyme loading capacity and optimum temperature and exhibited comparable re-use values and storage stability. Thus, a fast, easy, and less laborious method for lipase immobilization was developed.     

Inactivation of <Emphasis Type="Italic">Candida albicans</Emphasis> Biofilms on Polymethyl Methacrylate and Enhancement of the Drug Susceptibility by Cold Ar/O<Subscript>2</Subscript> Plasma Jet

The antimicrobial effects of the cold plasma for the dental pathogenic microorganism propose a promising approach to the Denture Stomatitis (DS) treatment. However, it is crucial to understand that the complexity of the biofilm microenvironment may compromise the efficiency of the therapy. As one of the major issue for DS, Candida albicans biofilms (ATCC10231) formed on denture base resins were treated by cold Ar/O₂ (2 %) plasma jet. Spatial viability of the biofilms was investigated with confocal scanning laser microscopy through evaluating their inside cross-section properties. Results showed Candida albicans biofilms with thickness of ~100 µm was completely inactivated by 8 min plasma treatment. Morphology change of the fungi was also observed by the scanning electron microscopy. Drug susceptibilities, the sessile minimum inhibitory concentration (SMIC50) of the biofilm for amphotericin B and fluconazole were decreased from >32 and >256 µg/mL to 8 and 64 µg/mL after 1 min’s plasma treatment, respectively. The reactive species produced from plasma were monitored by optical emission spectroscopy. The successfully inactivation of Candida albicans biofilms and the significant enhancement of its drug susceptibilities induced by the plasma released reactive species propose a promising strategy for the treatment of DS caused by drug-resistant Candida albicans biofilms.