Indoxyl Sulfate-Induced Macrophage Toxicity and Therapeutic Strategies in Uremic Atherosclerosis.

Cardiovascular disease (CVD) frequently occurs in patients with chronic kidney disease (CKD), particularly those undergoing dialysis. The mechanisms behind this may be related to traditional risk factors and CKD-specific factors that accelerate atherosclerosis and vascular calcification in CKD patients. The accumulation of uremic toxins is a significant factor in CKD-related systemic disorders. Basic research suggests that indoxyl sulfate (IS), a small protein-bound uremic toxin, is associated with macrophage dysfunctions, including increased oxidative stress, exacerbation of chronic inflammation, and abnormalities in lipid metabolism. Strategies to mitigate the toxicity of IS include optimizing gut microbiota, intervening against the abnormality of intracellular signal transduction, and using blood purification therapy with higher efficiency. Further research is needed to examine whether lowering protein-bound uremic toxins through intervention leads to a reduction in CVD in patients with CKD.

Impact of Controlling Nutritional Status Score on Comprehensive Clinical Outcomes in Patients With Chronic Limb-Threatening Ischemia in a Local Area of Super-Aged Society.

PURPOSE: This study aimed to evaluate the relationship between nutritional status and hospital outcomes in patients with chronic limb-threatening ischemia (CLTI) in a local area of contemporary super-aged society of Japan. MATERIALS AND METHODS: We analyzed 131 consecutive patients with 179 lower limb diseases admitted to our hospital for the treatment of CLTI between April 2018 and March 2023. These 131 patients were divided into 3 groups according to hospital outcomes: home discharge (HD), out-of-home discharge (OD), and in-hospital death (ID). Patient and lesion backgrounds were compared among the 3 groups, and a multivariable regression analysis was used to analyze the interaction between malnutrition and composite hard endpoints. RESULTS: The median age was 82.8 years, and non-ambulatory patients comprised 61.8% of the study population. The HD group included more ambulatory and fewer patients with higher CONUT score or inflammation than OD or ID group. The Rutherford classification and Wound, Ischemia, and foot Infection stage were significantly more severe in the ID group than in the HD group. Endovascular treatment (EVT) was more often implemented in the HD (94.9%) and OD (81.7%) groups than in the ID group (60.0%). However, all EVT procedures in the ID group were performed until as distally as possible to achieve the target arterial path success contrary to some EVT procedures in the HD or ID group that targeted lesions only above the knee. Multivariate analysis showed that a non-ambulatory state (hazard ratio [HR]=3.65, 95% confidence interval [CI]=1.48-9.02) and a higher controlling nutritional status (CONUT) score (≥5) (HR=7.46, 95% CI=1.66-33.6) were significant predictors for composite endpoints (major amputation or ID). Patients with lower CONUT scores (≤4) showed better outcomes in all indices including overall survival, major amputation-free survival, and wound healing. CONCLUSION: Condition of the CLTI patients represented by higher CONUT score emerged as the most influential predictor of major amputation or ID. Furthermore, non-ambulatory status or condition of higher CONUT score affects the destination after discharge. Implementing multidisciplinary approaches to address patients' nutritional state and physical disability, in addition to revascularization, may enhance comprehensive prognoses in patients with CLTI. CLINICAL IMPACT: In this single-center retrospective study, we analyzed prognoses of 131 consecutive patients with 179 lower limb diseases admitted for the treatment of chronic limb-threatening ischemia (CLTI) between April 2018 and March 2023. Our main finding was that condition of the CLTI patients represented by higher controlling nutritional status (CONUT) score was the most significant predictor of either major amputation or in-hospital death. Furthermore, condition of higher CONUT score or non-ambulatory status affects the destination after discharge. This suggests that multidisciplinary approaches to address patients' nutritional state and physical disability, in addition to revascularization, may enhance the prognosis in patients with CLTI. This is the first report to evaluate nutritional status associated with comprehensive hospital outcomes in addition to previously reported hard endpoints, such as major amputation or overall survival, and will be of great help in future clinical practice.

Simultaneous Injection of Contrast and Saline Using Spiral Flow-Generating Tube for Hepatic Dynamic Computed Tomography: Effect on Enhancement of Liver Parenchyma and Metastases to the Liver.

PURPOSE: Recently, there have been a few reports regarding the usefulness of a novel saline injection technique using a spiral flow-generating tube. The purpose of this study was to evaluate whether simultaneous saline injection using a spiral flow-generating tube was able to improve hepatic contrast enhancement and lesion conspicuity of metastatic liver tumors. METHODS: We randomized a total of 411 patients with various liver diseases including metastases by total body weight (A, n = 204) and contrast dilution protocol (B, n = 207). Group A received 400 mgI/kg of contrast medium alone without a spiral flow-generating tube; group B received contrast medium 400 mgI/kg simultaneous with injection of a 0.57-ml/kg physiologic saline solution through a spiral flow-generating tube. Abdominal aorta computed tomography (CT) number, hepatic enhancement (ΔHU), percentage of tests demonstrating an enhancement effect of the liver parenchyma exceeding Δ50 HU in 3 measured segments (S2, S6, and S8), and the contrast-to-noise ratio of the metastatic liver tumors were measured. RESULTS: The mean aortic CT number of group B (417.0 HU ± 61.7; P < 0.01) was approximately 10% higher than that of group A (384.6 ± 79.1 HU). The average ΔHU was 59.8 ± 11.4 HU for group A and 61.7 ± 11.7 for group B. The ΔHU for group B was significantly higher than that for group A (P = 0.017). The percentage of tests demonstrating with the enhancement effect of group B was more than 80% in all subgroups; however, that of group A was less than 80% in all subgroups. The contrast-to-noise ratio of group B (7.8 ± 3.3 HU) was significantly higher compared to that of group A (6.5 ± 2.8 HU) (P < 0.05). CONCLUSIONS: Because of the volume effect, injecting a contrast medium diluted with normal saline improved the degree of hepatic and aortic contrast enhancement and achieved better visualization of liver metastases. CLINICAL IMPACT: The use of spiral flow-generating tube may help diagnostic of hepatic and aortic contrast enhancement and liver metastases. IMPORTANCE: The use of a spiral flow-generating tube improved the degree of hepatic and aortic contrast enhancement and achieve better visualization of liver metastases. POINTS: The use of low-concentration syringe formulations is limited by body weight. However, the use of spiral flow-generating tube provides low-concentration contrast medium regardless of body weight.

Peripheral nerve regeneration following scaffold-free conduit transplant of autologous dermal fibroblasts: a non-randomised safety and feasibility trial.

BACKGROUND: The use of Bio 3D nerve conduits is a promising approach for peripheral nerve reconstruction. This study aimed to assess their safety in three patients with peripheral nerve defects in their hands. METHODS: We describe a single institution, non-blinded, non-randomised control trial conducted at Kyoto University Hospital. Eligibility criteria included severed peripheral nerve injuries or a defect in the region distal to the wrist joint not caused by a congenital anomaly; a defect with a length of ≤20 mm in a nerve with a diameter ≤2 mm; failed results of sensory functional tests; ability to register in the protocol within 6 months from the day of injury; refusal of artificial nerve or autologous nerve transplantation; age 20-60 years; and willingness to participate and provide informed written consent. Six weeks before transplantation, skin was harvested, dermal fibroblasts were isolated and expanded, and Bio 3D nerve conduits were created using a Bio 3D printer. Bio 3D nerve conduits were transplanted into the patients' nerve defects. The safety of Bio 3D nerve conduits in patients with a peripheral nerve injury in the distal part of the wrist joint were assessed over a 48-week period after transplantation. RESULTS: No adverse events related to the use of Bio 3D nerve conduits were observed in any patient, and all three patients completed the trial. CONCLUSIONS: Bio 3D nerve conduits were successfully used for clinical nerve reconstruction without adverse events and are a possible treatment option for peripheral nerve injuries.

Physical injuries often result in damage to nerves, for example, in the hands. Replacement of the nerve with nerves removed from elsewhere in the patient's body is often the suggested treatment when the nerve is unable to repair itself. As an alternative to remove healthy nerve from elsewhere in the body, we used an adapted printer to create an artificial nerve equivalent from skin cells obtained from the patient's skin. We reconstructed the nerves of three individual with nerve defects in their hands, and we found that the function of the nerve improved, and the people did not experience negative consequences. This approach could be used widely to repair damaged nerves.

A comparative observational study of carbohydrate intake and continuous blood glucose levels in relation to performance in ultramarathon.

Ultra-endurance events have gained global participation, whereas the critical factors of competition results remain to be well elucidated. This study used a nutritional approach to evaluate the association of competition results with carbohydrate intake and blood glucose control during a 100-mile ultramarathon. This observational study was conducted in the 2021 LAKE BIWA 100, which covered 100 miles (169 km) and 10,500 m elevation. The course was divided into 9 segments by aid station. According to the competition results, 22 participants (18 men and 4 women) were divided into higher finishers (n = 7), lower finishers (n = 9), and non-finishers (n = 6). The participants self-recorded their overall dietary intake throughout the race. Glucose levels were monitored every 15 min by a flash glucose monitoring system. Running speed in each segment was standardized to the average of the top five finishers for each gender. Among finishers, the carbohydrate intakes were significantly higher in the higher finishers than in the lower finishers during overall segments, especially in the first half of the race (p < 0.05). There was a significant positive correlation between running speed and carbohydrate intake in the lower finishers (rho = 0.700, p = 0.036). Two-way ANOVA analysis revealed that lowering glucose levels in each segment were more frequently observed in the lower finishers compared to the higher finishers (p = 0.012). Compared to the higher finishers, the lower finishers exhibited significantly greater fluctuations (⊿highest-lowest) in glucose levels (p < 0.001). The fluctuations in glucose levels were significantly and negatively correlated with the running speed of the finishers (rho = - 0.612, p = 0.012). Faster runners consume high amounts of carbohydrates and maintain glucose levels during the 100-mile ultramarathon on the trail, especially at the beginning. Lowering and fluctuating glucose levels during the race are associated with lower running speed in endurance athletes.

Removal of α1-Microglobulin Using Post-Dilution Online Hemodiafiltration with Polymethylmethacrylate Membrane: An Open-Label, Single-Arm Study.

INTRODUCTION: The removal of low- and medium-molecular-weight proteins has been improved with online hemodiafiltration (OL-HDF) and hemodialysis using high-flux membranes; however, the outcomes of patients with end-stage kidney disease (ESKD) undergoing dialysis treatment are still worse than in the general population. α1-Microglobulin (α1-m), with a molecular weight of 33,000 Da, may contribute to dialysis-related disorders and mortality. However, the removal is insufficient even with current OL-HDF using the polysulfone (PS) membrane, which is common in Japan. Polymethylmethacrylate (PMMA) membranes can remove medium- to high-molecular-weight proteins by adsorption. This study aimed to assess the efficacy of removing medium- to high-molecular-weight proteins, such as α1-m and ß2-microglobulin (ß2-m), through post-dilution OL-HDF with PMMA (Post-PMMA). The assessment was conducted in comparison to pre-dilution OL-HDF with PS (Pre-PS), using an open-label, single-arm study. METHODS: Seven patients with ESKD on Pre-PS underwent Post-PMMA with replacement volume of 30 mL/min (low flow) and 50 mL/min (high flow). Clearance and removal rates of α1-m, ß2-m, small molecules, inflammatory cytokines, and albumin were measured at 60 and 240 min of treatment. RESULTS: Clearance rates of α1-m at 60 min were -2.8 ± 5.2 mL/min with Pre-PS, -0.4 ± 2.6 mL/min with Post-PMMA (low), and 0.6 ± 3.4 mL/min with Post-PMMA (high). The removal rate of α1-m was higher in Post-PMMA than that in Pre-HDF-PS (Post-PMMA [high] 17.7 ± 5.9%, Post-PMMA [low] 15.0 ± 5.6%, and Pre-PS 4.1 ± 5.5%). Adsorption clearance of ß2-m was increased with Post-PMMA. Albumin leakage in Post-PMMA was not higher than that in Pre-PS. CONCLUSION: The removal rate of α1-m with Post-PMMA was higher than that with Pre-PS. The PMMA membrane adsorbed ß2-m, suggesting the removal effect of medium- to high-molecular-weight proteins by the adsorption method. Since Post-PMMA effectively removes α1-m without excessive albumin leakage, it will be useful for patients with ESKD, especially those with a poor nutritional status.

Emphysematous changes as red flag signs preceding rapidly progressive infectious aortic disease: two case reports.

BACKGROUND: Infectious aortic disease is a rare and fatal disease, that requires the appropriate intervention. An accurate diagnosis should be promptly established. However, this is difficult because the clinical manifestations of this disease vary and are non-specific. CASE PRESENTATION: (CASE 1) An 87-year-old male, presenting with generalized malaise and weight loss, was admitted for further examination. A chest computed tomography (CT) showed mediastinal emphysema. Empirical intravenous antibiotics were administered to address the non-specific infectious findings in the laboratory data. The treatment was effective, and the patient fully recovered. However, he was in shock due to aortic rupture and marked pseudo aneurysmal formation around the aortic arch day 25 of hospitalization. An emergency total aortic arch replacement was performed, and the patient was discharged. (CASE 2) An 82-year-old male who had undergone Y-graft replacement in the abdominal aorta 15 years previously was admitted due to general malaise and anorexia. Abdominal CT revealed emphysematous changes adjacent to the abdominal aorta. The patient responded favorably to empirical treatment with intravenous antibiotics and was discharged 19 days after admission. Four days after discharge, the patient went into cardiac arrest after an episode of hematemesis. Abdominal CT revealed an enlarged stomach and duodenum, filled with massive high-density contents proximal to the abdominal aorta. He died of hemorrhagic shock despite cardiopulmonary resuscitation. CONCLUSIONS: Although emphysematous changes are rare, they are red flag signs during the early stage of infectious aortic disease. Thus, physicians should remain vigilant for this kind of critical sign.

Effectiveness of a telenursing intervention program in reducing exacerbations in patients with chronic respiratory failure receiving noninvasive positive pressure ventilation: A randomized controlled trial.

Telenursing for patients with chronic respiratory failure receiving noninvasive positive pressure ventilation (NPPV) is an important aid in reducing exacerbations; however, there is insufficient evidence. This randomized controlled trial investigated the effectiveness of a telenursing intervention program in reducing exacerbations in patients with chronic respiratory failure receiving NPPV at home. We included patients receiving NPPV at home who could handle a tablet device. The intervention group (n = 15) underwent an information and communications technology-based telenursing intervention program in addition to usual care; the control group (n = 16) received the usual care only. The telenursing intervention program comprised telemonitoring and health counseling sessions via videophone. The intervention was evaluated once at enrollment and after 3 months. The primary endpoints were the number of unscheduled outpatient visits, hospitalizations, and hospital days. The secondary endpoints included the St. George's Respiratory Questionnaire (SGRQ) score, Euro QOL 5 Dimension score, Self-Care Agency Questionnaire (SCAQ) score, pulmonary function tests, and 6-min walking distance. We used the Mann-Whitney U test for our analysis. We found no significant differences between the intervention and control groups at enrollment. Then, the differences between the endpoints at baseline and 3 months after enrollment were calculated and used to compare both groups. At follow-up, the number of routine outpatient visits for acute exacerbations (p = .045), the number of hospitalizations (p = .037), the number of hospital days (p = .031), SGRQ (p = .039) score, and SCAQ (p = .034) score were significantly different. The increase in the number of unscheduled outpatient visits in the intervention group during follow-up was attributed to acute exacerbations and a significant decrease in the number of hospitalizations and hospital days. Hence, the telenursing intervention program may be effective in reducing exacerbations in patients with chronic respiratory failure receiving NPPV at home. Trial registration: UMIN Clinical Trials Registry (UMIN-CTR) UMIN000027657.

Development of the quality of life of family caregivers of advanced cancer patients scale in Japan: Psychometric properties.

Objective: We aimed to develop a new scale for use in Japan, called the "Quality of Life of Family Caregivers of Advanced Cancer Patients Scale (QFCS)" and to examine its psychometric properties. Methods: A draft scale was extracted based on qualitative inductive and deductive analyses, and its content validity and surface validity were investigated. Its psychometric properties were examined. Results: The QFCS consists of 30 items comprising four factors. Cronbach's α was 0.92 and the intraclass correlation coefficient was 0.90. Correlation coefficients between the total QFCS score and eight subscale scores of the revised Medical Outcomes Study 12-Item Short Form Survey Instrument were rs â€‹= â€‹0.22-0.65 (P â€‹< â€‹0.01-0.05). The Physical Component Summary was r â€‹= â€‹0.29 (P â€‹< â€‹0.01), and the Mental Component Summary was r â€‹= â€‹0.67 (P â€‹< â€‹0.01). Correlation coefficients between the QFCS total score and four subscale scores of the Caregiver Quality of Life Index-Cancer (CQOLC) were r â€‹= â€‹0.27-0.59 (P â€‹<0 â€‹.01) and the CQOLC total score was r â€‹= â€‹0.65 (P â€‹<0 â€‹.01). Conclusions: Our results suggest that the QFCS exhibited acceptable psychometric properties in measuring the quality of life of family caregivers of patients with advanced cancer. Future research is needed to evaluate the effectiveness and quality of family support using the QFCS.

Anti-skin-aging effects of human ceramides via collagen and fibrillin expression in dermal fibroblasts.

Intercellular lipids comprise mainly ceramides, known to enhance the barrier function of the stratum corneum. However, the activities of ceramides inside the skin have not yet been fully elucidated. Here we examined how the human ceramide mixture (HC123) functions in the dermis. We treated human skin fibroblasts with HC123-expressed fibroblast growth factor (FGF), transforming growth factor-ß (TGF-ß), collagen I, and fibrillin. We found that HC123 promoted the formation of collagen fibers and microfibrils (fibrillin) which affect the elasticity of the skin. We also confirmed that the gene expression of collagen and fibrillin is promoted via TGF-ß and FGF2, respectively. We then investigated the permeability of HC123 for external use, in pursuit of evidence that HC123 may exert an anti-aging effect by penetrating into the dermis, activating fibroblasts, and promoting the production of collagen fibers and elastin-related microfibrils.

Development of the opioid self-management scale for advanced Cancer patients with pain and examination of its validity and reliability.

BACKGROUND: Approximately 60% of outpatients with advanced cancer experience pain; therefore, self-management of opioid use is important for appropriate pain relief. To date, no studies have clearly described the concept of opioid self-management or assessed the factors involved, including the improvement of self-management abilities. This study developed, and evaluated the validity and reliability of an opioid self-management scale for advanced cancer patients with pain (OSSA). Opioid self-management in advanced cancer patients with pain was defined as the management of opioid medication performed by patients with advanced cancer to relieve cancer pain on their own. METHODS: Three phases were required for validation and reliability of the OSSA: 1) testing content validity, 2) testing face validity, and 3) testing construct validity, concurrent validity and reliability. RESULTS: After a three-phase process, the OSSA consisted of 33 items on six subscales. The structural equation modeling was such that the χ2 value was 709.8 (p < 0.001, df = 467), goodness-of-fit index was 0.78, adjusted goodness-of-fit index was 0.73, root mean squares of approximation was 0.063, and comparative fit index was 0.92. The Pearson correlation coefficients between the total OSSA score and the 24-hour average pain or pain relief over 24 hours were - 0.21 (p < 0.05) and 0.26 (p < 0.01), respectively. Cronbach's α was 0.93. The intraclass correlation coefficient range was 0.59-0.90. CONCLUSION: The findings of this study show that the OSSA has acceptable validity and reliability, and that better self-management leads to greater pain relief. The OSSA can be considered effective for use in research, but shortened version should be prepared for realistic and practical clinical use.

Effects of hot­water extracts from 26 herbs on α­glucosidase activity.

α­glucosidase is a key enzyme that plays a role in glucose absorption in the gastrointestinal tract, and the inhibition of its activity induces the prevention of postprandial hyperglycemia. Several α­glucosidase inhibitors have been used as medicines for type 2 diabetes, but a similar effect is observed in natural resources, including traditional herbs and their phytochemicals. To identify the presence of the α­glucosidase inhibitory activity in herbs, in which various functional effects have been known to occur, the present study investigated the effects of hot­water extracts of 26 types of herbs on α­glucosidase activity in an in vitro assay. The results indicated significant increases in the inhibition of α­glucosidase activity in 1,000 µg/ml olive (P<0.01), white willow (P<0.01) and red rooibos hot­water extracts. Furthermore, ≥50% inhibition of α­glucosidase activity was determined to be significant in 1,000 µg/ml coltsfoot, green tea and bearberry hot­water extracts. In addition, the effects of bearberry, green tea and coltsfoot hot­water extracts on α­glucosidase activity in vivo were evaluated according to the blood glucose levels (BGLs) in maltose and glucose load model rats. It was indicated that the administration of these three herb extracts significantly reduced the increasing BGLs after maltose loading until 0.5 h compared with the control group. However, only coltsfoot extract significantly reduced the increasing BGLs after glucose loading until 0.5 h compared with the control group. Thus, the present results may facilitate the understanding of a novel functionality in traditional herbs, which could be useful for the prevention of disease onset and progression, such as in hyperglycemia and type 2 diabetes.

Production of pyruvate from mannitol by mannitol-assimilating pyruvate decarboxylase-negative Saccharomyces cerevisiae.

Mannitol is contained in brown macroalgae up to 33% (w/w, dry weight), and thus is a promising carbon source for white biotechnology. However, Saccharomyces cerevisiae, a key cell factory, is generally regarded to be unable to assimilate mannitol for growth. We have recently succeeded in producing S. cerevisiae that can assimilate mannitol through spontaneous mutations of Tup1-Cyc8, each of which constitutes a general corepressor complex. In this study, we demonstrate production of pyruvate from mannitol using this mannitol-assimilating S. cerevisiae through deletions of all 3 pyruvate decarboxylase genes. The resultant mannitol-assimilating pyruvate decarboxylase-negative strain produced 0.86 g/L pyruvate without use of acetate after cultivation for 4 days, with an overall yield of 0.77 g of pyruvate per g of mannitol (the theoretical yield was 79%). Although acetate was not needed for growth of this strain in mannitol-containing medium, addition of acetate had a significant beneficial effect on production of pyruvate. This is the first report of production of a valuable compound (other than ethanol) from mannitol using S. cerevisiae, and is an initial platform from which the productivity of pyruvate from mannitol can be improved.

Acquisition of the ability to assimilate mannitol by Saccharomyces cerevisiae through dysfunction of the general corepressor Tup1-Cyc8.

Saccharomyces cerevisiae normally cannot assimilate mannitol, a promising brown macroalgal carbon source for bioethanol production. The molecular basis of this inability remains unknown. We found that cells capable of assimilating mannitol arose spontaneously from wild-type S. cerevisiae during prolonged culture in mannitol-containing medium. Based on microarray data, complementation analysis, and cell growth data, we demonstrated that acquisition of mannitol-assimilating ability was due to spontaneous mutations in the genes encoding Tup1 or Cyc8, which constitute a general corepressor complex that regulates many kinds of genes. We also showed that an S. cerevisiae strain carrying a mutant allele of CYC8 exhibited superior salt tolerance relative to other ethanologenic microorganisms; this characteristic would be highly beneficial for the production of bioethanol from marine biomass. Thus, we succeeded in conferring the ability to assimilate mannitol on S. cerevisiae through dysfunction of Tup1-Cyc8, facilitating production of ethanol from mannitol.

Regulation of pH attenuates toxicity of a byproduct produced by an ethanologenic strain of Sphingomonas sp. A1 during ethanol fermentation from alginate.

Marine macroalgae is a promising carbon source that contains alginate and mannitol as major carbohydrates. A bioengineered ethanologenic strain of the bacterium Sphingomonas sp. A1 can produce ethanol from alginate, but not mannitol, whereas the yeast Saccharomyces paradoxus NBRC 0259-3 can produce ethanol from mannitol, but not alginate. Thus, one practical approach for converting both alginate and mannitol into ethanol would involve two-step fermentation, in which the ethanologenic bacterium initially converts alginate into ethanol, and then the yeast produces ethanol from mannitol. In this study, we found that, during fermentation from alginate, the ethanologenic bacterium lost viability and secreted toxic byproducts into the medium. These toxic byproducts inhibited bacterial growth and killed bacterial cells and also inhibited growth of S. paradoxus NBRC 0259-3. We discovered that adjusting the pH of the culture supernatant or the culture medium containing the toxic byproducts to 6.0 attenuated the toxicity toward both bacteria and yeast, and also extended the period of viability of the bacterium. Although continuous adjustment of pH to 6.0 failed to improve the ethanol productivity of this ethanologenic bacterium, this pH adjustment worked very well in the two-step fermentation due to the attenuation of toxicity toward S. paradoxus NBRC 0259-3. These findings provide information critical for establishment of a practical system for ethanol production from brown macroalgae.

Bacterial pyruvate production from alginate, a promising carbon source from marine brown macroalgae.

Marine brown macroalgae is a promising source of material for biorefining, and alginate is one of the major components of brown algae. Despite the huge potential availability of alginate, no system has been reported for the production of valuable compounds other than ethanol from alginate, hindering its further utilization. Here we report that a bacterium, Sphingomonas sp. strain A1, produces pyruvate from alginate and secretes it into the medium. High aeration and deletion of the gene for d-lactate dehydrogenase are critical for the production of high concentrations of pyruvate. Pyruvate concentration and productivity were at their maxima (4.56 g/l and 95.0 mg/l/h, respectively) in the presence of 5% (w/v) initial alginate, whereas pyruvate produced per alginate consumed and % of theoretical yield (0.19 g/g and 18.6%, respectively) were at their maxima at 4% (w/v) initial alginate. Concentration of pyruvate decreased after it reached its maximum after cultivations for 2 or 3 days at 145 strokes per minute. Our study is the first report to demonstrate the production of other valuable compounds than ethanol from alginate, a promising marine macroalgae carbon source.