The protective effect of L-theanine addition to a cryoprotectant on the storage viability of lactic acid bacteria.

Lactic acid bacteria (LAB) that metabolize sugars to obtain energy and produce a large amount of lactate through the process are well known for their benefits. However, they can be used on a large scale only when good storage stability is guaranteed. The vitality and stability of several LAB strains were effectively protected in this investigation by L-theanine at 1% of the appropriate concentration (Lactiplantibacillus plantarum MG5023, Enterococcus faecium MG5232, Lactococcus lactis MG4668, Streptococcus thermophilus MG5140, and Bifidobacterium animalis subsp. lactis MG741). The inclusion of L-theanine as a protective agent significantly enhanced the viability of all strains throughout the freeze-drying process compared to that of the non-coated probiotics. The efficacy of L-theanine in improving bacterial stability and survivability was evaluated using accelerated stability tests, gastrointestinal (GI) tract survivability tests, and adhesion assays with intestinal epithelial cells. The cell surface was covered with substances including L-theanine, according to morphological findings, providing efficient defense against a variety of external stresses. Therefore, by exerting anti-freezing and anti-thawing properties, the adoption of L-theanine as a new and efficient protective agent may improve the stability and viability of a variety of probiotics.

Antioxidant and Anti-Inflammatory Effect and Probiotic Properties of Lactic Acid Bacteria Isolated from Canine and Feline Feces.

Oxidative stress is a phenomenon caused by an imbalance between the production of reactive oxygen species and antioxidant defenses. It plays an important role in numerous disease states, including chronic kidney disease, neurological disorders, cardiovascular diseases, diabetes, and cancer. Lactic acid bacteria (LAB) are known to have prominent antioxidant properties. Therefore, this study aimed to measure the antioxidant activity and anti-inflammatory potential of LAB isolated from animals for the efficient use of probiotics with host specificity. Antioxidant activity measurements of sixteen strains revealed that ABTS radical scavenging activities ranged from 26.3 to 57.4%, and DPPH free radical scavenging activities ranged from 4.7 to 13.5%. Based on the antioxidant activity assessment, five strains (Enterococcus faecium MG9003(YH9003), Enterococcus faecium MG9007(YH9007), Lactobacillus reuteri MG9012(YH9012), Lactobacillus fermentum MG9014(YH9014), and Pediococcus pentosaceus MG9015(YH9015)) were selected with the consideration of fermentation productivity (>1 × 109 CFU/g). The selected strains exhibited nitric oxide inhibition and inhibited inducible nitric oxide synthase and cyclooxygenase expression. Furthermore, probiotic properties, including intestinal adhesion and stability, were identified. Our results show that the selected animal-derived strains can be effective probiotic candidates for potential effects on animal hosts.

Bioleaching for environmental remediation of toxic metals and metalloids: A review on soils, sediments, and mine tailings.

Owing to industrial evolution, a huge mass of toxic metals, including Co, Cu, Cr, Mn, Ni, Pb, and Zn, and metalloids, such as As and Sb, has inevitably been released into the natural environment and accumulated in soils or sediments. Along with modern industrialization, many mineral mines have been explored and exploited to provide materials for industries. Mining industries also generate a vast amount of waste, such as mine tailings, which contain a high concentration of toxic metals and metalloids. Due to the low economic status, a majority of mine tailings are simply disposed into the surrounding environments, without any treatment. The mobilization and migration of toxic metals and metalloids from soils, sediments, and mining wastes to water systems via natural weathering processes put both the ecological system and human health at high risk. Considering both economic and environmental aspects, bioleaching is a preferable option for removing the toxic metals and metalloids because of its low cost and environmental safety. This chapter reviews the recent approaches of bioleaching for removing toxic metals and metalloids from soils, sediments, and mining wastes. The comparison between bioleaching and chemical leaching of various waste sources is also discussed in terms of efficiency and environmental safety. Additionally, the advanced perspectives of bioleaching for environmental remediation with consideration of other influencing factors are reviewed for future studies and applications.

Effects of Probiotic Culture Supernatant on Cariogenic Biofilm Formation and RANKL-Induced Osteoclastogenesis in RAW 264.7 Macrophages.

Postbiotics are a promising functional ingredient that can overcome the limitations of viability and storage stability that challenge the production of probiotics. To evaluate the effects of postbiotics on oral health, eight spent culture supernatants (SCSs) of probiotics were prepared, and the effects of SCSs on Streptococcus mutans-induced cariogenic biofilm formation and the receptor activator of the nuclear factor κB ligand (RANKL)-induced osteoclastogenesis were evaluated in RAW 264.7 macrophages. SCS of Lactobacillus salivarius MG4265 reduced S. mutans-induced biofilm formation by 73% and significantly inhibited tartrate-resistant acid phosphatase (TRAP) activity, which is a biomarker of mature osteoclasts in RAW 264.7 macrophages. The suppression of RANKL-induced activation of mitogen activated the protein kinases (c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38) and nuclear factor κB pathways, as well as the upregulation of heme oxygenase-1 expression. The suppression of RANK-L-induced activation of mitogen also inhibited the expression of transcriptional factors (c-fos and nuclear factor of activated T cells cytoplasmic 1) and, subsequently, osteoclastogenesis-related gene expression (tartrate-resistant acid phosphatase-positive (TRAP), cathepsin K, and matrix metalloproteinase-9).Therefore, SCS of L. salivarius MG4265 has great potential as a multifunctional oral health ingredient that inhibits biofilm formation and suppresses the alveolar bone loss that is associated with periodontitis.

Battery-Free and Noninvasive Estimation of Food pH and CO2 Concentration for Food Monitoring Based on Pressure Measurement.

In this paper, we developed a battery-free system that can be used to estimate food pH level and carbon dioxide (CO2) concentration in a food package from headspace pressure measurement. While being stored, food quality degrades gradually as a function of time and storage conditions. A food monitoring system is, therefore, essential to prevent the detrimental problems of food waste and eating spoilt food. Since conventional works that invasively measure food pH level and CO2 concentration in food packages have shown several disadvantages in terms of power consumption, system size, cost, and reliability, our study proposes a system utilizing package headspace pressure to accurately and noninvasively extract food pH level and CO2 concentration, which reflection food quality. To read pressure data in the food container, a 2.5 cm × 2.5 cm smart sensor tag was designed and integrated with near-field communication (NFC)-based energy harvesting technology for battery-free operation. To validate the reliability of the proposed extraction method, various experiments were conducted with different foods, such as pork, chicken, and fish, in two storage environments. The experimental results show that the designed system can operate in a fully passive mode to communicate with an NFC-enabled smartphone. High correlation coefficients of the headspace pressure with the food pH level and the headspace CO2 concentration were observed in all experiments, demonstrating the ability of the proposed system to estimate food pH level and CO2 concentration with high accuracy. A linear regression model was then trained to linearly fit the sensor data. To display the estimated results, we also developed an Android mobile application with an easy-to-use interface.

A Bipolar-Channel Hybrid Brain-Computer Interface System for Home Automation Control Utilizing Steady-State Visually Evoked Potential and Eye-Blink Signals.

The goal of this study was to develop and validate a hybrid brain-computer interface (BCI) system for home automation control. Over the past decade, BCIs represent a promising possibility in the field of medical (e.g., neuronal rehabilitation), educational, mind reading, and remote communication. However, BCI is still difficult to use in daily life because of the challenges of the unfriendly head device, lower classification accuracy, high cost, and complex operation. In this study, we propose a hybrid BCI system for home automation control with two brain signals acquiring electrodes and simple tasks, which only requires the subject to focus on the stimulus and eye blink. The stimulus is utilized to select commands by generating steady-state visually evoked potential (SSVEP). The single eye blinks (i.e., confirm the selection) and double eye blinks (i.e., deny and re-selection) are employed to calibrate the SSVEP command. Besides that, the short-time Fourier transform and convolution neural network algorithms are utilized for feature extraction and classification, respectively. The results show that the proposed system could provide 38 control commands with a 2 s time window and a good accuracy (i.e., 96.92%) using one bipolar electroencephalogram (EEG) channel. This work presents a novel BCI approach for the home automation application based on SSVEP and eye blink signals, which could be useful for the disabled. In addition, the provided strategy of this study-a friendly channel configuration (i.e., one bipolar EEG channel), high accuracy, multiple commands, and short response time-might also offer a reference for the other BCI controlled applications.

Detection of Driver Braking Intention Using EEG Signals During Simulated Driving.

In this work, we developed a novel system to detect the braking intention of drivers in emergency situations using electroencephalogram (EEG) signals. The system acquired eight-channel EEG and motion-sensing data from a custom-designed EEG headset during simulated driving. A novel method for accurately labeling the training data during an extremely short period after the onset of an emergency stimulus was introduced. Two types of features, including EEG band power-based and autoregressive (AR)-based, were investigated. It turned out that the AR-based feature in combination with artificial neural network classifier provided better detection accuracy of the system. Experimental results for ten subjects indicated that the proposed system could detect the emergency braking intention approximately 600 ms before the onset of the executed braking event, with high accuracy of 91%. Thus, the proposed system demonstrated the feasibility of developing a brain-controlled vehicle for real-world applications.

Ethanol production from water hyacinth (Eichhornia crassipes) hydrolysate by hyper-thermal acid hydrolysis, enzymatic saccharification and yeasts adapted to high concentration of xylose.

Water hyacinth (Eichhornia crassipes) was used as a feedstock for ethanol production. The optimal hyper-thermal (HT) acid hydrolysis conditions were 8% (w/v) slurry content, 200 mM H2SO4, at 160 °C for 20 min and enzymatic saccharification for 48 h using an enzyme mixture of 20 units/mL Viscozyme L and Cellic C Tec2. After pretreatment, 48.2 g/L monosaccharides were obtained. Fermentation was conducted with wild and adapted Saccharomyces cerevisiae, Pichia stipitis and Candida lusitaniae. Wild-type S. cerevisiae, P. stipitis, and C. lusitaniae produced 15.3, 19.5 and 22.7 g/L of ethanol, respectively. Adaptive evolution was carried out on 6% (w/v) xylose. S. cerevisiae, P. sipitis and C. lusitaniae adapted to xylose produced 15.3, 21.4 and 23.9 g/L of ethanol with YEtOH of 0.32, 0.44 and 0.49, respectively. These results indicate that water hyacinth has potential as a feed stock for ethanol.

Correction to: Butanol and butyric acid production from Saccharina japonica by Clostridium acetobutylicum and Clostridium tyrobutyricum with adaptive evolution.

Unfortunately, the author name was wrongly published as Pailin Sukwang.instead of Pailin Sukwong.

Butanol and butyric acid production from Saccharina japonica by Clostridium acetobutylicum and Clostridium tyrobutyricum with adaptive evolution.

Optimal conditions of hyper thermal (HT) acid hydrolysis of the Saccharina japonica was determined to a seaweed slurry content of 12% (w/v) and 144 mM H2SO4 at 160 °C for 10 min. Enzymatic saccharification was carried out at 50 °C and 150 rpm for 48 h using the three enzymes at concentrations of 16 U/mL. Celluclast 1.5 L showed the lowest half-velocity constant (Km) of 0.168 g/L, indicating a higher affinity for S. japonica hydrolysate. Pretreatment yielded a maximum monosaccharide concentration of 36.2 g/L and 45.7% conversion from total fermentable monosaccharides of 79.2 g/L with 120 g dry weight/L S. japonica slurry. High cell densities of Clostridium acetobutylicum and Clostridium tyrobutyricum were obtained using the retarding agents KH2PO4 (50 mM) and NaHCO3 (200 mM). Adaptive evolution facilitated the efficient use of mixed monosaccharides. Therefore, adaptive evolution and retarding agents can enhance the overall butanol and butyric acid yields from S. japonica.

Detoxification of Hydrolysates of the Red Seaweed Gelidium amansii for Improved Bioethanol Production.

In this study, bioethanol was produced from the seaweed Gelidium amansii as biomass through separate hydrolysis and fermentation (SHF) processes. The SHF processes examined in this study include thermal acid hydrolysis pretreatment, enzymatic saccharification, detoxification, and fermentation. Thermal acid hydrolysis pretreatment was conducted using H2SO4, with a slurry content of 8-16% and treatment time of 15-75 min. The optimal conditions for thermal acid hydrolysis pretreatment were 12% (w/v) seaweed slurry content and 180 mM H2SO4 at 121 °C for 45 min, at which 26.1 g/L galactose and 6.8 g/L glucose were produced. A monosaccharide (mainly glucose) was also obtained from the enzymatic saccharification of thermal acid hydrolysate using 16 U/mL Celluclast 1.5 L enzyme at 45 °C for 36 h. Detoxification was performed using the adsorption method with activated carbon, the overliming method with Ca (OH)2, and the ion exchange method with polyethyleneimine. Among those detoxification methods, activated carbon showed the best performance for hydroxymethylfurfural removal. Ethanol fermentation was performed using 12% (w/v) seaweed hydrolysate with Saccharomyces cerevisiae adapted to galactose as well as various detoxification treatments.

Kinetics of microbial selenite reduction by novel bacteria isolated from activated sludge.

A total of three bacteria isolated from activated sludge of a wastewater treatment plant were found to reduce selenite to elemental selenium nanoparticles as both amorphous nanospheres and monoclinic nanocrystals. The three isolated strains, which are potential candidates for bioremediation of selenite-contaminated water sources, were designated as Citrobacter sp. NVK-2, Providencia sp. NVK-2A, and Citrobacter sp. NVK-6 based on 16S rRNA sequencing. Despite belonging to the same genus, the kinetics of selenite reduction by strain NVK-2 (Vmax = 58.82 µM h-1, Km = 3737.12 µM) completely differed from that of strain NVK-6 (Vmax = 19.23 µM h-1, Km = 1300.17 µM). The selenite reduction rate by strain NVK-2A (Vmax = 9.26 µM h-1, Km = 3044.73 µM) was the slowest among the investigated microorganisms. The microbial selenite reduction rates according to various organic sources indicated that simple organic sources such as acetate and lactate were better than more complex organic sources such as propionate, butyrate, and glucose for selenite removal. Interestingly, the selenite reduction rate was significantly enhanced when the organic source was strategically divided into small portions and consecutively supplied to the culture.

Acetone, butanol, and ethanol production from the green seaweed Enteromorpha intestinalis via the separate hydrolysis and fermentation.

Acetone, butanol, and ethanol (ABE) were produced following the separate hydrolysis and fermentation (SHF) method using polysaccharides from the green macroalgae Enteromorpha intestinalis as biomass. We focused on the optimization of enzymatic saccharification as pretreatments for the fermentation of E. intestinalis. Pretreatment was carried out with 10% (w/v) seaweed slurry and 270-mM H2SO4 at 121 °C for 60 min. Monosaccharides (mainly glucose) were obtained from enzymatic hydrolysis with a 16-U/mL mixture of Celluclast 1.5 L and Viscozyme L at 45 °C for 36 h. ABE fermentation with 10% (w/v) E. intestinalis hydrolysate was performed using the anaerobic bacteria Clostridium acetobutylicum with either uncontrolled pH, pH controlled at 6.0, or pH controlled initially at 6.0 and then 4.5 after 4 days, which produced ABE contents of 5.6 g/L with an ABE yield (YABE) of 0.24 g/g, 4.8 g/L with an YABE of 0.2 g/g, and 8.5 g/L with an YABE of 0.36 g/g, respectively.

Bioethanol Production from Soybean Residue via Separate Hydrolysis and Fermentation.

Bioethanol was produced using polysaccharide from soybean residue as biomass by separate hydrolysis and fermentation (SHF). This study focused on pretreatment, enzyme saccharification, and fermentation. Pretreatment to obtain monosaccharide was carried out with 20% (w/v) soybean residue slurry and 270 mmol/L H2SO4 at 121 °C for 60 min. More monosaccharide was obtained from enzymatic hydrolysis with a 16 U/mL mixture of commercial enzymes C-Tec 2 and Viscozyme L at 45 °C for 48 h. Ethanol fermentation with 20% (w/v) soybean residue hydrolysate was performed using wild-type and Saccharomyces cerevisiae KCCM 1129 adapted to high concentrations of galactose, using a flask and 5-L fermenter. When the wild type of S. cerevisiae was used, an ethanol production of 20.8 g/L with an ethanol yield of 0.31 g/g consumed glucose was obtained. Ethanol productions of 33.9 and 31.6 g/L with ethanol yield of 0.49 g/g consumed glucose and 0.47 g/g consumed glucose were obtained in a flask and a 5-L fermenter, respectively, using S. cerevisiae adapted to a high concentration of galactose. Therefore, adapted S. cerevisiae to galactose could enhance the overall ethanol fermentation yields compared to the wild-type one.

Enhancement of Ethanol Production via Hyper Thermal Acid Hydrolysis and Co-Fermentation Using Waste Seaweed from Gwangalli Beach, Busan, Korea.

The waste seaweed from Gwangalli beach, Busan, Korea was utilized as biomass for ethanol production. Sagassum fulvellum (brown seaweed, Mojaban in Korean name) comprised 72% of the biomass. The optimal hyper thermal acid hydrolysis conditions were obtained as 8% slurry contents, 138 mM sulfuric acid, and 160°C of treatment temperature for 10 min with a low content of inhibitory compounds. To obtain more monosaccharides, enzymatic saccharification was carried out with Viscozyme L for 48 h. After pretreatment, 34 g/l of monosaccharides were obtained. Pichia stipitis and Pichia angophorae were selected as optimal co-fermentation yeasts to convert all of the monosaccharides in the hydrolysate to ethanol. Co-fermentation was carried out with various inoculum ratios of P. stipitis and P. angophorae. The maximum ethanol concentration of 16.0 g/l was produced using P. stipitis and P. angophorae in a 3:1 inoculum ratio, with an ethanol yield of 0.47 in 72 h. Ethanol fermentation using yeast co-culture may offer an efficient disposal method for waste seaweed while enhancing the utilization of monosaccharides and production of ethanol.

Bioethanol Production Using Waste Seaweed Obtained from Gwangalli Beach, Busan, Korea by Co-culture of Yeasts with Adaptive Evolution.

Conditions for ethanol production were evaluated using waste seaweed obtained from Gwangalli beach, Busan, Korea, after strong winds on January 15, 2015. Eleven types of seaweed were identified, and the proportions of red, brown, and green seaweed wastes were 26, 46, and 28%, respectively. Optimal pretreatment conditions were determined as 8% slurry content, 286 mM H2SO4 for 90 min at 121 °C. Enzymatic saccharification with 16 units/mL Celluclast 1.5L and Viscozyme L mixture at 45 °C for 48 h was carried out as optimal condition. A maximum monosaccharide concentration of 30.2 g/L was obtained and used to produce ethanol. Fermentation was performed with single or mixed yeasts of non-adapted and adapted Saccharomyces cerevisiae KCTC 1126 and Pichia angophorae KCTC 17574 to galactose and mannitol, respectively. The maximum ethanol concentration and yield of 13.5 g/L and YEtOH of 0.45 were obtained using co-culture of adapted S. cerevisiae and P. angophorae.

Bioethanol production from Gracilaria verrucosa using Saccharomyces cerevisiae adapted to NaCl or galactose.

This study examined the pretreatment, enzymatic saccharification, and fermentation of the red macroalgae Gracilaria verrucosa using adapted saccharomyces cerevisiae to galactose or NaCl for the increase of bioethanol yield. Pretreatment with thermal acid hydrolysis to obtain galactose was carried out with 11.7% (w/v) seaweed slurry and 373 mM H2SO4 at 121 °C for 59 min. Glucose was obtained from enzymatic hydrolysis. Enzymatic saccharification was performed with a mixture of 16 U/mL Celluclast 1.5L and Viscozyme L at 45 °C for 48 h. Ethanol fermentation in 11.7% (w/v) seaweed hydrolysate was carried out using Saccharomyces cerevisiae KCTC 1126 adapted or non-adapted to high concentrations of galactose or NaCl. When non-adapted S. cerevisiae KCTC 1126 was used, the ethanol productivity was 0.09 g/(Lh) with an ethanol yield of 0.25. Ethanol productivity of 0.16 and 0.19 g/(Lh) with ethanol yields of 0.43 and 0.48 was obtained using S. cerevisiae KCTC 1126 adapted to high concentrations of galactose and NaCl, respectively. Adaptation of S. cerevisiae KCTC 1126 to galactose or NaCl increased the ethanol yield via adaptive evolution of the yeast.

Temperature feedback-controlled photothermal treatment with diffusing applicator: theoretical and experimental evaluations.

To minimize thermal injury, the current study evaluated the real-time temperature monitoring with a proportional-integrative-derivative (PID) controller during 980-nm photothermal treatment with a radially-diffusing applicator. Both simulations and experiments demonstrated comparable thermal behaviors in temperature distribution and the degree of irreversible tissue denaturation. The PID-controlled application constantly maintained the pre-determined temperature of 353 K (steady-state error = < 1 K). Due to constant energy delivery, coagulation volumes linearly increased up to 1.04 ± 0.02 cm(3) with irradiation time. Integration of temperature feedback with diffuser-assisted photothermal treatments can provide a feasible therapeutic modality to treat pancreatic tumors in an effective manner.

Evaluation of Galactose Adapted Yeasts for Bioethanol Fermentation from Kappaphycus alvarezii Hydrolyzates.

Bioethanol was produced from Kappaphycus alvarezii seaweed biomass using separate hydrolysis and fermentation (SHF). Pretreatment was evaluated for 60 min at 121°C using 12% (w/v) biomass slurry with 364 mM H2SO4. Enzymatic saccharification was then carried out at 45°C for 48 h using Celluclast 1.5 L. Ethanol fermentation with 12% (w/v) K. alvarezii hydrolyzate was performed using the yeasts Saccharomyces cerevisiae KCTC1126, Kluyveromyces marxianus KCTC7150, and Candida lusitaniae ATCC42720 with or without prior adaptation to high concentrations of galactose. When non-adapted S. cerevisiae, K. marxianus, and C. lusitaniae were used, 11.5 g/l, 6.7 g/l, and 6.0 g/l of ethanol were produced, respectively. When adapted S. cerevisiae, K. marxianus, and C. lusitaniae were used, 15.8 g/l, 11.6 g/l, and 13.4 g/l of ethanol were obtained, respectively. The highest ethanol concentration was 15.8 g/l, with YEtOH = 0.43 and YT% = 84.3%, which was obtained using adapted S. cerevisiae.

Evaluation of hyper thermal acid hydrolysis of Kappaphycus alvarezii for enhanced bioethanol production.

Hyper thermal (HT) acid hydrolysis of Kappaphycus alvarezii, a red seaweed, was optimized to 12% (w/v) seaweed slurry content, 180mM H2SO4 at 140°C for 5min. The maximum monosaccharide concentration of 38.3g/L and 66.7% conversion from total fermentable monosaccharides of 57.6g/L with 120gdw/L K. alvarezii slurry were obtained from HT acid hydrolysis and enzymatic saccharification. HT acid hydrolysis at a severity factor of 0.78 efficiently converted the carbohydrates of seaweed to monosaccharides and produced a low concentration of inhibitory compounds. The levels of ethanol production by separate hydrolysis and fermentation with non-adapted and adapted Kluyveromyces marxianus to high concentration of galactose were 6.1g/L with ethanol yield (YEtOH) of 0.19 at 84h and 16.0g/L with YEtOH of 0.42 at 72h, respectively. Development of the HT acid hydrolysis process and adapted yeast could enhance the overall ethanol fermentation yields of K. alvarezii seaweed.