Co-encapsulated astaxanthin and kaempferol nanoparticles: fabrication, characterization, and their potential synergistic effects on treating non-alcoholic fatty liver disease.

Astaxanthin and kaempferol, renowned natural compounds, possess potent antioxidant properties and exhibit remarkable biological activities. However, their poor water solubility, low stability, and limited bioavailability are the primary bottlenecks that restrict their utilization in pharmaceuticals and functional foods. To overcome these drawbacks, this study aims to fabricate astaxanthin/kaempferol co-encapsulated nanoparticles and investigate their synergistic effects on reducing the risk of stress oxidation, chronic inflammation, and lipid accumulation in RAW264.7 and HepG2 cells. The synthesized astaxanthin/kaempferol nanoparticles exhibited well-defined spherical morphology with an average particle diameter ranging from 74 to 120 nm. These nanoparticles demonstrated excellent stability with the remaining astaxanthin content ranging from 82.5% to 92.1% after 6 months of storage at 4 °C. Nanoastaxanthin/kaempferol displayed high dispersibility and stability in aqueous solutions, resulting in a significant enhancement of their bioactivity. In vitro assessments on cell lines revealed that nanoastaxanthin/kaempferol enhanced the inhibition of H2O2-induced oxidative stress in HepG2 and LPS-induced NO production in RAW264.7 compared to nanoastaxanthin. Additionally, these nanoparticles reduced the expression of genes involved in inflammation (iNOS, IL-6 and TNF-α). Moreover, hepatocytes treated with nanoastaxanthin/kaempferol showed a reduction in lipid content compared to those treated with nanoastaxanthin, through enhanced regulation of lipid metabolism-related genes. Overall, these findings suggest that the successful fabrication of co-encapsulated nanoparticles containing astaxanthin and kaempferol holds promising therapeutic potential in the treatment of non-alcoholic fatty liver disease.

Ensemble learning of myocardial displacements for myocardial infarction detection in echocardiography.

Background: Early detection and localization of myocardial infarction (MI) can reduce the severity of cardiac damage through timely treatment interventions. In recent years, deep learning techniques have shown promise for detecting MI in echocardiographic images. Existing attempts typically formulate this task as classification and rely on a single segmentation model to estimate myocardial segment displacements. However, there has been no examination of how segmentation accuracy affects MI classification performance or the potential benefits of using ensemble learning approaches. Our study investigates this relationship and introduces a robust method that combines features from multiple segmentation models to improve MI classification performance by leveraging ensemble learning. Materials and Methods: Our method combines myocardial segment displacement features from multiple segmentation models, which are then input into a typical classifier to estimate the risk of MI. We validated the proposed approach on two datasets: the public HMC-QU dataset (109 echocardiograms) for training and validation, and an E-Hospital dataset (60 echocardiograms) from a local clinical site in Vietnam for independent testing. Model performance was evaluated based on accuracy, sensitivity, and specificity. Results: The proposed approach demonstrated excellent performance in detecting MI. It achieved an F1 score of 0.942, corresponding to an accuracy of 91.4%, a sensitivity of 94.1%, and a specificity of 88.3%. The results showed that the proposed approach outperformed the state-of-the-art feature-based method, which had a precision of 85.2%, a specificity of 70.1%, a sensitivity of 85.9%, an accuracy of 85.5%, and an accuracy of 80.2% on the HMC-QU dataset. On the external validation set, the proposed model still performed well, with an F1 score of 0.8, an accuracy of 76.7%, a sensitivity of 77.8%, and a specificity of 75.0%. Conclusions: Our study demonstrated the ability to accurately predict MI in echocardiograms by combining information from several segmentation models. Further research is necessary to determine its potential use in clinical settings as a tool to assist cardiologists and technicians with objective assessments and reduce dependence on operator subjectivity. Our research codes are available on GitHub at https://github.com/vinuni-vishc/mi-detection-echo.

The effects of pretreatment with Cyclosporin A and Docetaxel before vitrification of porcine immature oocytes on subsequent embryo development.

In the present study, we attempted to improve the developmental competence of vitrified immature porcine oocytes by the preservation of mitochondrial properties using Cyclosporin A (CsA, inhibitor of mitochondrial membrane permeability transition) and Docetaxel (stabilizer of microtubules, hence mitochondrial distribution). In Experiment 1, Mitotracker red staining revealed reduced mitochondrial activity (MA) in vitrified/warmed oocytes at 0 and 22 h of in vitro maturation (IVM) compared with fresh ones. However, by at 46 h of IVM, MA levels in vitrified oocytes were similar to those in fresh control. Treatment of oocytes with CsA or Docetaxel improved MA at 0 h and 22 h of IVM compared with non-treated vitrified oocytes. However, there were no significant differences among groups in percentages of survival, maturation and embryo development after subsequent IVM and parthenogenetic activation. Nevertheless, a pretreatment with a combination of 10 µg/mL CsA and 0.05 µM Docetaxel improved the blastocyst formation of vitrified oocytes compared with non-treatment counterparts (11.2 ± 1.6% vs 5.9 ± 1.6%, P < 0.05). In conclusion, vitrification reduced mitochondrial activity in GV-stage oocytes during 0-22 h of IVM; however, it was normalized by 46 h IVM. Docetaxel or CsA pretreatment alone did not improve development competence of vitrified oocytes. However, pretreatment with a combination of CsA and Docetaxel could improve blastocyst formation rates.

Distribution and 24-hour transition of SCAI shock stages and their association with 30-day mortality in acute myocardial infarction.

The Society for Cardiovascular Angiography and Interventions (SCAI) shock classification has been shown to predict mortality in acute myocardial infarction (AMI). However, data on the transition of SCAI stages and their association with mortality after AMI are limited. All patients with AMI admitted to Vietnam National Heart Institute between August 2022 and February 2023 were classified into SCAI stages A, B, and C/D/E at admission and were reevaluated in 24 hours. We used Kaplan-Meier estimate and multivariable Cox regression analysis to assess the association between SCAI stages transition and 30-day mortality. We included 139 patients (median age 69 years, 29.5% female). On admission, 50.4%, 20.1%, and 29.5% of patients were classified as SCAI stage A, B, and C/D/E, respectively. The proportion of patients whose SCAI stage improved, remained stable, or worsened after 24 hours was 14.4%, 66.2%, and 19.4%, respectively. The 30-day mortality in patients with initial SCAI stages A, B, and C/D/E on admission was 2.9%, 21.4%, and 61.0%, respectively (P < .001). The 30-day mortality was 2.4% for patients with baseline SCAI stage A/B who remained unchanged or improved, 30.0% for patients with baseline SCAI stage C/D/E who remained unchanged or improved, and 92.6% for patients with SCAI stage B/C/D/E who worsened at 24 hours after admission (log-rank P < .001). In patients with AMI, evaluating the SCAI stage shock stage on admission and reevaluating after 24 hours added more information about 30-day mortality.

Malignant cerebral edema after cranioplasty, a rare complication: case series and literature review.

Cranioplasty is standard neurosurgery performed after decompressive craniectomy. Fatal malignant cerebral oedema complications associated with this procedure are rare and clinically distinct, although unpredictable. It is thought that the pressure difference from removing atmospheric pressure had a long-term effect on the brain. This combined with the negative pressure applied by intraoperative pressure drainage may impact the perfusion brain. Here, the authors report four cases of cerebral oedema after cranioplasty and review similar cases in the literature. Case presentation: The authors report on four cases of patients who underwent cranioplasty following decompressive craniotomy and subsequently died after surgery. Three of the patients had undergone craniotomy following trauma, while one patient had skull resorption. All four patients developed cerebral oedema immediately after surgery and exhibited significant craniofacial depression (also known as sunk flap syndrome). A negative pressure drainage system was utilized in all cases. One patient remained intubated, while the remaining three developed postoperative epilepsy and subsequently fell into a coma. Dilated and fixed pupils were observed in all patients, and computed tomography scans revealed diffuse cerebral oedema. Despite intensive resuscitation efforts and attempts at decompression, all four patients ultimately succumbed to their conditions. Conclusion: Fatal post-cranioplasty malignant cerebral oedema is a rare but very dangerous complication. Despite being rare, neurosurgeons should be aware that this fatal complication can occur after cranioplasty.

Dibutyryl-cAMP and roscovitine differently affect premature meiotic resumption and embryo development of vitrified immature porcine oocytes.

Vitrification and warming can trigger premature meiosis in immature porcine oocytes. Our aim was to compare the efficacies of two meiotic inhibitors, dibutyryl-cAMP and roscovitine for the meiosis synchronization during in vitro maturation (IVM) of porcine oocytes vitrified at the germinal vesicle (GV) stage. We first compared the efficacy of 1 mM dibutyryl-cAMP and 25 µM roscovitine on meiotic arrest during the first 22 h of IVM. Dibutyryl-cAMP could maintain the GV stage in 83.5% of oocytes; however, roscovitine was even more effective (96.6%), whereas only 17.4% of the oocytes remained at the GV stage without these additives. Temporal meiotic arrest for 22 h by roscovitine did not reduce the percentage of oocytes reaching the Metaphase II stage during subsequent IVM. However, after parthenogenetic stimulation or in vitro fertilization, subsequent embryo development to the blastocyst stage was compromised after roscovitine treatment, whereas dibutyryl-cAMP improved the percentage of blastocyst development. In conclusion, dibutyryl-cAMP could derogate but not completely prevent premature meiosis in vitrified oocytes, whereas roscovitine could more efficiently prevent it. However, for embryo production, the use of roscovitine was disadvantageous, whereas the use of dibutyryl-cAMP was beneficial.

Reduction in Plasmodium falciparum Pfk13 and pfg377 allele diversity through time in southern Vietnam.

BACKGROUND: Plasmodium falciparum has acquired resistance to artemisinin in Southeast Asia, with mutations in the P. falciparum Kelch-13 (Pfk13) gene associated with the resistance phenotype. The widespread use of Artemisinin-based combination therapy (ACT)s in Southeast Asia has led to the selection and spread of parasites carrying mutations in Pfk13. We characterised the allele diversity of Pfk13 and pfg377, an artemisinin-resistance neutral polymorphic gene, in parasite DNA extracted human blood from in southern Vietnam in 2003, 2012, 2015 and 2018. METHOD: This study was conducted in Bu Gia Map commune, Binh Phuoc province, Vietnam, from May 2018 to January 2019. Twenty-four samples from 2018 to 2019, 30 from 2003, 24 from 2012 and 32 from 2015 were analysed. Malaria-infected human blood was collected by finger-prick and used for molecular analysis. A nested-PCR targeting the small subunit ribosomal RNA gene was used for Plasmodium species identification, followed by amplification and nucleotide sequencing of Pfk13 and region 3 of pfg377. Archived blood samples collected in the same region in 2012 and 2015 were also analysed as above for comparison. RESULTS: The genetic diversity of Pfk13 and pfg377 was lower in 2018-2019 compared to 2012 and 2015. The number of distinct Pfk13 mutants decreased from three in 2012 and 2015, P553L, V568G and C580Y, to one, C580Y in 2018-2019. In 2018-2019, the frequency of C580Y mutant strains was 71% (17/24 isolates). All samples were wild type in 2003. In 2012 and 2015, there were single-strain infections as well as co-infections with two mutant strains or with mutant and wild strains, whereas there were no co-infections in 2018. pfg377 allele diversity decreased from five alleles in 2012 to two alleles in 2018-2019. CONCLUSION: The genetic diversity of P. falciparum was reduced at the two genetic loci surveyed in this study, Pfk13 and pfg377. In the case of the former gene, we observed an increase in the prevalence of parasites carrying the C580Y gene, known to confer reduced susceptibility to ACTs. The reduction in the diversity of pfg377 may be linked to the clonal expansion of parasite strains carrying the C580Y mutation, leading to an overall reduction in parasite genetic diversity across the population.

Duodenal perforation as a postoperative complication after ventriculoperitoneal shunt: A case report.

INTRODUCTION AND IMPORTANCE: Ventriculoperitoneal shunt (VP shunt) is the one of the most common and important tools for the treatment of hydrocephalus. It requires simple technique and demonstrates effectiveness in treating hydrocephalus. However, many complications have been reported such as infection, valve obstruction, valve dysfunction and abdominal complications. Complications of intestinal perforation and catheter penetrating the intestine are very rare, accounting for 0.01-0.07% of abdominal complications. In the literature, 94 cases of intestinal perforation and catheter penetration and only 2 cases of duodenal perforation have been reported. CASE PRESENTATION: In this study, we report a successful surgical treatment of a duodenal perforation complication after 5 months of VP shunt. Gastroscopy showed the distal tip penetrating into the D2 segment of the duodenum. Surgery was performed to relocate the abdominal tip and to repair the perforation. Meningitis was treated with antibiotics. The patient was stable and discharged after 3 weeks. CLINICAL DISCUSSION: The epidermiology, presentation and diagnosis and strategy of treatments as well as their outcomes were discussed. CONCLUSION: Intestinal perforation with VP shunt catheter is rare. Diagnosis is simple if the catheter comes out of the anus, mouth, vagina, penis, scrotum, navel. In case when the catheter is inside the lumen of the gastrointestinal tract, diagnosis often requires imaging such as abdominal computed tomography, and gastrointestinal endoscopy. Surgery treatment was to replace the drainage valve and to close the perforation the digestive tract.

Efficient Isolation and Long-term Red Fluorescent Nanodia-mond Labeling of Umbilical Cord Mesenchymal Stem Cells for the Effective Differentiation into Hepatocyte-like Cells

Abstract Fluorescent nanodiamond (FND) has been used for long-term cell labeling and in vivo cell tracking because they have good at photostability and biocompatibility. In this study, we evaluate the effect of fluorescent nanodiamond labeling on in vitro culture and differentiation of human umbilical cord mesenchymal stem cells (hUCMSCs) into hepatocyte-like cells (HLCs). For hepatic differentiation of hUCMSCs, cells were induced with human hepatocyte growth factor, nicotinamide and Dexamethasone. FND was supplied in two experimental groups with 20 μg/mL and 100 μg/mL in 2 hours. The cell was assessed for FND uptake by laser scan microscopy and flow cytometry methods. The effect of FND on hUCMSCs was evaluated by the cell viability and growth assays as well as the differentiation throughout of morphology alterations or gene expression of anfa-fetoprotein, albumin, and hepatocyte nuclear factor 4α. The results showed that the labeling of hUCMSCs is efficient and easy and there was significant cellular uptake of FND. We did not observe any negative impacts of FND to the cell viability and growth. FND can be utilized for the long-term labeling and tracking of hUCSCs and HLCs in vivo studies.

High-level expression, purification and properties of an Endochitinase gene without signal peptide from Lecanicillium lecanii 43H in Pichia pastoris.

Chitinases play the key role in hydrolysis of chitin, a huge organic carbon reservoir on earth, into monomeric sugars and their eventual conversion into valuable chemicals and energy sources. The Lecanicillium lecanii strain 43H was used as the source for the Endochitinase gene without signal peptide (mchit1). This mchit1 gene was cloned and sequenced. The recombinant Endochitinase non signal peptide was overexpressed in Pichia pastoris X33 with a level of 2.048 U mL-1 culture supernatant. The molecular mass of the purified recombinant Endochitinase (rmchit1) without signal peptide was 43 kDa. Metal ions, detergents, and organic solvents tested indicated a significantly influence on rmchit1 activity. The obtained results demonstrated that signal peptides affect the yield expression, purification methods, recovery as well as the physicochemical properties of the enzyme.

A Circo-Like Virus Isolated from Penaeus monodon Shrimps.

A virus with a circular Rep-encoding single-stranded DNA (ssDNA) (CRESS-DNA) genome (PmCV-1) was isolated from Penaeus monodon shrimps in Vietnam. The gene structure of the 1,777-nucleotide (nt) genome was similar to that of circoviruses and cycloviruses, but the nucleic acid and protein sequence identities to these viruses were very low.

Fertilization ability of porcine oocytes reconstructed from ooplasmic fragments produced and characterized after serial centrifugations.

Mitochondria are reported to be critical in in vitro maturation of oocytes and subsequent embryo development after fertilization, but their contribution for fertilization has not been investigated in detail. In the present study, we investigate the contribution of mitochondria to fertilization using reconstructed porcine oocytes by fusion of ooplasmic fragments produced by serial centrifugations (centri-fusion). Firstly, we evaluated the characteristics of ooplasmic fragments. Three types of fragments were obtained by centrifugation of porcine oocytes matured in vitro for 46 h: brownish (B), transparent (T) and large (L) fragments containing both B and T parts in a fragment. The production efficiencies of these types of fragments were 71.7, 91.0 and 17.8 fragments/100 oocytes, respectively. In experiments, L fragments were excluded because they contained both brownish and transparent components that were apparently intermediate between B and T fragments. Observations by confocal microscopy after staining with MitoTracker Red CMXRos® and transmission electron microscopy revealed highly condensed active mitochondria in B fragments in contrast to T fragments that contained only sparse organelles. We reconstructed oocytes by fusion of a karyoplast and two cytoplasts from B and T fragments (B and T oocytes, respectively). The B oocytes showed higher sperm penetration (95.8%) and male pronuclear formation rates (94.2%) by in vitro fertilization than T oocytes (66.7% and 50.0%, respectively). These results suggest that the active mitochondria in oocytes may be related to their ability for fertilization.

Assessment of pregnancy-associated glycoprotein (PAG) concentrations in swamp buffalo samples from fetal and maternal origins by using interspecies antisera.

Pregnancy-associated glycoproteins (PAG) constitute a large family of glycoproteins found in the outer placental epithelial cell layer of the placenta in Eutherian species. In ruminants, they are noted to be structurally closely related among the different species. This study was designed to determine PAG concentrations in maternal and fetal plasma, allantoic and amniotic fluids in buffalo species. Antisera (AS) generated in rabbits against distinct PAG molecules were used in three radioimmunoassay (RIA)-PAG systems: RIA-1 (antiserum raised against bovine PAG67kDa; AS#497), RIA-2 (antiserum raised against caprine PAG55 + 62 kDa; AS#706) or RIA-3 (antiserum raised against buffalo PAG; AS#859). Samples were collected at a slaughterhouse (n = 67). PAG concentrations determined by RIA-2 gave significantly higher results in both allantoic and amniotic fluids (12.7 ± 2.1 ng/mL and 24.0 ± 7.3 ng/mL, respectively). Regarding maternal and fetal plasma, PAG concentrations obtained by RIA-2 (21.8 ± 2.4 ng/mL and 20.2 ± 2.5 ng/mL, respectively) and RIA-3 (25.0 ± 2.2 ng/mL and 21.9 ± 3.2 ng/mL, respectively) were higher than those obtained by RIA-1 (15.5 ± 1.4 ng/mL and 16.1 ± 1.8 ng/mL, respectively). The correlation among the three systems was very high. The study clearly reveals the ability of different PAG-RIA systems to measure PAG concentration in swamp buffalo samples.

Improvement of cellulase activity using error-prone rolling circle amplification and site-directed mutagenesis.

Improvement of endoglucanase activity was accomplished by utilizing error-prone rolling circle amplification, supplemented with 1.7 mM MnCl2. This procedure generated random mutations in the Bacillus amyloliquefaciens endoglucanase gene with a frequency of 10 mutations per kilobase. Six mutated endoglucanase genes, recovered from six colonies, possessed endoglucanase activity between 2.50- and 3.12-folds higher than wild type. We sequenced these mutants, and the different mutated sites of nucleotides were identified. The mutated endoglucanase sequences had five mutated amino acids: A15T, P24A, P26Q, G27A, and E289V. Among these five substitutions, E289V was determined to be responsible for the improved enzyme activity. This observation was confirmed with site-directed mutagenesis; the introduction of only one mutation (E289V) in the wild-type endoglucanase gene resulted in a 7.93-fold (5.55 U/mg protein) increase in its enzymatic activity compared with that (0.7 U/mg protein) of wild type.

Improvement of fungal cellulase production by mutation and optimization of solid state fermentation.

Spores of Aspergillus sp. SU14 were treated repeatedly and sequentially with Co(60) γ-rays, ultraviolet irradiation, and N-methyl-N'-nitro-N-nitrosoguanidine. One selected mutant strain, Aspergillus sp. SU14-M15, produced cellulase in a yield 2.2-fold exceeding that of the wild type. Optimal conditions for the production of cellulase by the mutant fungal strain using solid-state fermentation were examined. The medium consisted of wheat-bran supplemented with 1% (w/w) urea or NH(4)Cl, 1% (w/w) rice starch, 2.5 mM MgCl(2), and 0.05% (v/w) Tween 80. Optimal moisture content and initial pH was 50% (v/w) and 3.5, respectively, and optimal aeration area was 3/100 (inoculated wheat bran/container). The medium was inoculated with 25% 48 hr seeding culture and fermented at 35℃ for 3 days. The resulting cellulase yield was 8.5-fold more than that of the wild type strain grown on the basal wheat bran medium.

Accuracy of transrectal palpation for early pregnancy diagnosis in Egyptian buffaloes.

The present study was undertaken to evaluate the accuracy of transrectal palpation (TRP) for diagnosing early pregnancy in buffaloes and the false diagnoses of the TRP test by using the pregnancy-associated glycoprotein radioimmunoassay (PAG-RIA) test. Pregnancy was diagnosed in 168 buffalo-cows once by TRP and PAG-RIA test between days 31 and 55 after breeding. The sensitivity of TRP for detecting pregnant buffalo-cows was 37.5% at days 31-35, increased to 93.8% at days 46-50 and reached 100% at days 51-55 (P < 0.01). All cases of false negative diagnoses (n = 10) had PAG concentration higher than the threshold (≥1.8 ng/mL) for diagnosing pregnancy. The specificity of TRP for detecting non-pregnant buffalo cows ranged between 90.9%, and 100% between days 31 and 55. All cases of false positive diagnoses (n = 5) made by TRP had PAG concentrations lower than the threshold for diagnosing pregnancy. It could be concluded that TRP is an accurate method for diagnosing pregnant and non-pregnant buffalo cows from day 46 after breeding.

Improvement of fungal strain by repeated and sequential mutagenesis and optimization of solid state fermentation for the hyper-production of raw-starch-digesting enzyme.

A selected fungal strain, for production of the raw-starchdigesting enzyme by solid-state fermentation, was improved by two repeated sequential exposures to gamma-irradiation of Co60, ultraviolet, and four repeated treatments with Nmethyl- N'-nitrosoguanidine. The mutant strain Aspergillus sp. XN15 was chosen after a rigorous screening process, with its production of the raw-starch-digesting enzyme being twice that of usual wild varieties cultured under preoptimized conditions and in an unsupplemented medium. After 17 successive subculturings, the enzyme production of the mutant was stable. Optimal conditions for the production of the enzyme by solid-state fermentation, using wheat bran as the substrate, were accomplished for the mutant Aspergillus sp. XN15. With the optimal fermentation conditions, and a solid medium supplemented with nitrogen sources of 1% urea and 1% NH4NO3, 2.5 mM CoSO4, 0.05% (v/w) Tween 80, and 1% glucose, the mutant Aspergillus sp. XN15 produced the raw-starch-digesting enzyme in quantities 19.4 times greater than a typical wild variety. Finally, XN15, through simultaneous saccharification and fermentation of a raw rice corn starch slurry, produced a high level of ethanol with Yp/s of 0.47 g/g.

Longitudinal survey of Plasmodium falciparum infection in Vietnam: characteristics of antimalarial resistance and their associated factors.

Plasmodium falciparum is the main cause of human malaria and is one of the important pathogens causing high rates of morbidity and mortality. The total number of malaria patients in Vietnam has gradually decreased over the last decade. However, the spread of pathogens with drug resistance remains a significant problem. Defining the trend in genotypes related to drug resistance is essential for the control of malaria in Vietnam. We undertook a longitudinal survey of Plasmodium falciparum malaria in 2001, 2002, and 2005 to 2007. The pfcrt, pfmdr1, pfdhfr, and pfdhps genes were analyzed by sequencing; and correlations by study year, age, gender, and genotype were identified statistically. The ratio of the chloroquine resistance genotype pfcrt 76T was found to have decreased rapidly after 2002. High numbers of mutations in the pfdhfr and pfdhps genes were observed only in 2001 and 2002, while the emergence of parasites with a new K540Y mutation in the P. falciparum dihydropteroate synthetase (PfDHPS) was observed in 2002. For males and those in younger age brackets, a correlation between vulnerability to P. falciparum infection and strains with pfcrt 76K or strains with decreased numbers of mutations in pfdhfr and pfdhps was demonstrated. The parasites with pfcrt 76T exhibited a greater number of mutations in pfdhfr and pfdhps.

Ethanol production from rice winery waste-rice wine cake by simultaneous saccharification and fermentation without cooking.

Ethanol production by simultaneous saccharification and fermentation (SSF) of low-value rice wine cake (RWC) without cooking was investigated. RWC is the filtered solid waste of fermented rice wine mash and contains 53% of raw starch. RWC slurry was mixed with raw-starch-digesting enzyme of Rhizopus sp. and yeast for SSF. The yeast strain used was selected from 300 strains for RWC fermentation and identified as Saccharomyces cerevisiae KV25. High efficiency (94%) of ethanol production was achieved at optimal condition of uncooked RWC slurry containing 23.03% of starch. The optimal SSF condition determined was 1.125 unit of raw-starch-digesting enzyme per one gram of RWC, 30 degrees C of fermentation temperature, 4.5 of pH slurry, 36 h-age of seeding culture, initial yeast cell 2 x 10(7) per ml slurry, 17 mM urea as nitrogen additive, 0.25 mM Cu(2+) as metal ion additives, 90 h of fermentation time. In this optimal condition, ethanol production by SSF of uncooked RWC slurry was improved to 16.8% (v/v) from 15.1% (v/v) of pre-optimization.

High-cell-density fed-batch culture of Saccharomyces cerevisiae KV-25 using molasses and corn steep liquor.

High-cell-density cultivation of yeast was investigated using the agricultural waste products corn steep liquor (CSL) and molasses. The Saccharomyces cerevisiae KV-25 cell mass was significantly dependent on the ratio between C and N sources. The concentrations of molasses and CSL in the culture medium were statistically optimized at 10.25% (v/v) and 16.87% (v/v), respectively, by response surface methodology (RSM). Batch culture in a 5-l stirred tank reactor using the optimized medium resulted in a cell mass production of 36.5 g/l. In the fed-batch culture, the feed phase was preceded by a batch phase using the optimized medium, and a very high dried-cell-mass yield of 187.63 g/l was successfully attained by feeding a mixture of 20% (v/v) molasses and 80% (v/v) CSL at a rate of 22 ml/h. In this system, the production of cell mass depended mainly on the agitation speed, the composition of the feed medium, and the glucose level in the medium, but only slightly on the aeration rate.