The current linear economy model relies on fossil energy and increases CO₂ emissions, which contributes to global warming and environmental pollution. Therefore, there is an urgent need to develop and deploy technologies for carbon capture and utilization to establish a circular economy. The use of acetogens for C1-gas (CO and CO₂) conversion is a promising technology due to high metabolic flexibility, product selectivity, and diversity of the products including chemicals and fuels. This review focuses on the physiological and metabolic mechanisms, genetic and metabolic engineering modifications, fermentation process optimization, and carbon atom economy in the process of C1-gas conversion by acetogens, with the aim to facilitate the industrial scale-up and carbon negative production through acetogen gas fermentation.
Fermentation ; Gases/metabolism* ; Carbon Dioxide/metabolism* ; Metabolic Engineering ; Carbon/metabolism*

To evaluate the ability of microbial mix-culture fermenting syngas into ethanol, we studied the microbial mix-cultures A-fm 4, G-fm 4, Lp-fm 4 and B-fm 4 obtained by enrichment and compared with Clostridium autoethanogenum DSM10061 with 10% and 25% inoculation size. The results show that, with 10% inoculation size, the ethanol production of A-fm 4, G-fm 4, Lp-fm 4, B-fm 4 and C. autoethanogenum were 349.15, 232.16, 104.25, 79.90 and 26.99 mg/L respectively. With 25% inoculation size, the ethanol production were 485.81, 472.73, 348.58, 272.52 and 242.15 mg/L respectively. Higher inoculation size will increase the production of ethanol. The tested mix-culture exhibited a significant yield advantage compared with the maximum production of C. autoethanogenum reported in the literature (259.64 mg/L). This research provided a practical method to improve ethanol production from syngas.
Bacteria ; classification ; metabolism ; Clostridium acetobutylicum ; metabolism ; Ethanol ; isolation & purification ; metabolism ; Fermentation ; Gases ; metabolism ; Hydrogen ; metabolism

BACKGROUND: It is well known that administration of nutrients, especially protein and amino acids mixtures, stimulates energy expenditure in the unanesthetized patients. Also, there were reports that the mechanisms for nutrient-induced thermogenesis are not impaired during general anaesthesia. The enhanced amino acid-induced thermogenesis would counteract the anaesthesia-induced reduction in metabolism and prevent the development of hypothermia. The present study was designed to see if completing the amino acid infusion before induction of anaesthesia would induce heat production, which would promote energy expenditure and thereby counteract the development of anaesthesia-induced hypothermia. METHODS: Body temperatures and arterial blood gases were measured in 48 patients during perioperative period. 24 patients had an amino acid mixture of 227 cal infused over 2 hours before anesthesia and 24 control patients received Hartman's solution. RESULTS: Amino acid infusion attenuated the development of hypothermia during the period from 60 min to 105 min after induction of anaesthesia compared to control group, however, did not prevent overall hypothermia throughout the study period. CONCLUSION: This result may indicate amino acid infusion before anesthesia can be an adjuvant to prevent intraoperative hypothermia.
Amino Acids ; Anesthesia ; Body Temperature ; Energy Metabolism ; Gases ; Humans ; Hypothermia ; Metabolism ; Perioperative Period ; Thermogenesis

Adult ; Female ; Gases ; Humans ; Intestine, Small ; metabolism ; microbiology ; physiology ; Liver Cirrhosis ; metabolism ; microbiology ; Male ; Middle Aged

Escherichia coli AFP111 is a spontaneous mutant with mutations in the glucose specific phosphotransferase system (ptsG) in NZN111 (delta pflAB deltaldhA). In AFP111, conversion of xylose to succinic acid generates 1.67 molecule of ATP per xylose. However, the strain needs 2.67 molecule ATP for xylose metabolism. Therefore, AFP111 cannot use xylose due to insufficient ATP under anaerobic condition. Through an atmospheric and room temperature plasma (ARTP) jet, we got a mutant strain named DC111 that could use xylose under anaerobic condition in M9 medium to produce succinic acid. After 72 h, DC111 consumed 10.52 g/L xylose to produce 6.46 g/L succinic acid, and the yield was 0.78 mol/mol. Furthermore, the reaction catalyzed by the ATP-generating PEP-carboxykinase (PCK) was enhanced. The specific activity of PCK was 19.33-fold higher in DC111 than that in AFP111, which made the strain have enough ATP to converse xylose to succinic acid.
Atmosphere ; Escherichia coli ; genetics ; metabolism ; Fermentation ; Industrial Microbiology ; Metabolic Engineering ; Mutation ; Plasma Gases ; pharmacology ; Succinic Acid ; metabolism ; Temperature ; Xylose ; metabolism

Chronic obstructive pulmonary disease (COPD) is characterized by a not entirely reversible limitation in the airflow. An airflow limitation is progressive and associated with an abnormal inflammatory response of the lung to gases and harmful particles. In COPD, the weight loss is commonly observed and there is a negative impact on the respiratory as well as skeletal muscle function. The pathophysiological mechanisms that result in weight loss in COPD are not fully understood. However, the mechanisms of weight loss in COPD may be the result of an increased energy expenditure unbalanced by an adequate dietary intake. The commonly occurring weight loss and muscle wasting in COPD patients adversely affect the respiratory and peripheral muscle function, the exercise capacity, the health status, and even the survival rates. Therefore, it is very valuable to include management strategies that the increase energy balance in order to increase the weight and fat free mass. A Better understanding of the molecular and cellular pathological mechanisms of COPD can improve the many new directions for both the basic and clinical investigations. The Nutritional supply is an important components of a multidisciplinary pulmonary rehabilitation program. Future studies combining an exercise program, the role of anabolic steroids, nutritional individualization, a more targeted nutritional therapy, and the development of new drugs including anti-cytokines is needed for the effective management of COPD.
Energy Metabolism ; Gases ; Humans ; Lung ; Muscle, Skeletal ; Pulmonary Disease, Chronic Obstructive* ; Rehabilitation ; Steroids ; Survival Rate ; Weight Loss

We present a case of portal and superior mesenteric venous gas in a 31-year-old diabetic woman with a left-sided retroperitoneal abscess. Five years prior to admission, patient was diagnosed with diabetes mellitus and developed emphysematous pyelonephritis, requiring nephrectomy on the left side. A CT examination showed air distributed throughout the portal venous system and superior mesenteric vein.
Abscess/blood/*radiography ; Adult ; Female ; Gases/blood ; Humans ; Mesenteric Veins/metabolism/*radiography ; Portal Vein/metabolism/*radiography ; Retroperitoneal Space ; Tomography, X-Ray Computed

OBJECTIVESTo explore relationship between rat brain tissues hurts of gas explosion and the expression of Protein Kinase C alpha mRNA.

METHODSBuild up rat hurt model of gas explosion. In Situ Hybridization (IDH) technique was used to test Protein Kinase C alpha mRNA. Immunohistochemical Assays (IHA) was used to determine c-fos gene protein.

RESULTSOnly a little a mount expression of PKC alpha mRNA and c-fos of the control group was detected. The expression of the cerebral cortex and hippocampus of PKC alpha mRNA 24 h, 48 h and the 48 h increased obviously, and the 48 h reached the peak of expression; (t = 4.12 P < 0.01). The expression of c-fos protein of the cerebral cortex and hippocampus started to increase obviously at 0.5 h and the 4 h reached the peak, then the strength lowered gradually and the expression level came back normal level on fifth day.

CONCLUSIONThe anoxia of brain tissues due to the gas explosion may promote the expression of PKCamRNA, and PKCamRNA could regulate the expression of the gene of c-fos. Both PKCamRNA and the gene of c-fos are involved in harmful processes to the nerve cells.

Animals ; Brain ; metabolism ; Brain Injuries ; metabolism ; Disease Models, Animal ; Explosions ; Hypoxia ; metabolism ; Protein Kinase C-alpha ; metabolism ; Proto-Oncogene Proteins c-fos ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Tear Gases

BACKGROUND: Thiopental has a profound impact on the cardiovascular system. The effects of hemody namics after intravenous thiopental on the balance of cerebral metabolism with cerebral blood flow is unknown. The purpose of this study was to monitor hemodynamic change, cerebral arterial-jugular venous oxygen content difference (AVDO2) and jugular venous oxygen saturation (SjVO2) after a thiopental injection for brain protection during cerebral aneurysm surgery. METHODS: Twenty patients received a standard anesthetic consisting of isoflurane, vecuronium and fentanyl with a PaCO2 of 30 35 mmHg. Hemodynamics, arterial and jugular venous blood gases were measured at 3 time points:I; Just before thiopental injection; II; Electroencephalographic (EEG) burst suppression after a 4 5 mg/kg intravenous thiopental injection; and III; EEG recovery. RESULTS: Intravenous thiopental (4 5 mg/kg) induced an EEG burst suppression for 6.5 +/- 1.7 minutes. Hemodynamics and arterial blood gas analysis were not significantly different among the different time points, but mean arterial pressure (68.4 +/- 7.2 mmHg) and systemic vascular resistance (1027.0 +/- 300.9 dynes sec/cm5) in II were significantly (P < 0.05) decreased compared with I (84.3 +/- 9.6, 1169.1 +/- 304.5) and III (89.1 +/- 10.6, 1288.6 +/- 426.1). SjVO2 (71.6 +/- 11.8%) was significantly (p < 0.05) decreased within the normal value compared with I (75.1 +/- 5.6) and III (76.1 +/- 10.1), but AVDO2 was not significantly different among the 3 time points. There was no evidence of cerebral ischemia or infarction in computed tomographic (CT) findings of the 20 patients after surgery. CONCLUSIONS: Hemodynamics after 4 5 mg/kg intravenous thiopental do not modify the balance ofcerebral oxygen metabolism with cerebral blood flow in patients undergoing cerebral aneurysm surgery.
Arterial Pressure ; Blood Gas Analysis ; Brain ; Brain Ischemia ; Cardiovascular System ; Electroencephalography ; Fentanyl ; Gases ; Hemodynamics ; Humans ; Infarction ; Intracranial Aneurysm* ; Isoflurane ; Metabolism ; Oxygen* ; Reference Values ; Thiopental* ; Vascular Resistance ; Vecuronium Bromide

BACKGROUND: The CO2 concentration in exhaled gases is intrinsically linked to tissue metabolism, ventilation, and pulmonary circulation. In hemodynamically stable patients, the end-tidal CO2(PetCO2) is known to be a good index of arterial CO2 (PaCO2). However, the PetCO2 has some limitations in predicting PaCO2 in emergent patients with unstable vital signs. OBJECTIVE: We evaluated the relationship of PetCO2 and PaCO2 and the validity of the difference between PetCO2 and PaCO2(PaCO2-PetCO2) for various clinical situations. MATERIAL AND METHOD: A prospective analysis was performed in endotracheally intubated patients, who presented at the Korea University Emergency Medical Center during a 14-month period from January 2003 to February 2004. Patients were divided into three groups; respiratory insufficiency of cardiopulmonary cause (Group A), respiratory insufficiency of extracardiopulmonary cause (Group B), cardiac arrest with any cause (Group C). Group A was subdivided into two subgroups; A1 with a history of chronic lung disease disease and A2 with no history of chronic lung disease history. In each group, the mean of PaCO2-PetCO2 was calculated and multiple comparison was performed in each groups by using a one-way ANOVA test, and the 95% confidence interval of PaCO2 - PetCO2 was calculated. P a C O2 and PetCO2 were evaluated by using a linear regression analysis. The calculation was performed using the SPSS for windows version 10.0, and p values of less than 0.05 were considered significant. RESULT: A total of 59 patients were included in this study. Twenty-five patients were in Group A, (18 in A1 and 7 in A2), 26 in Group B, and 8 in Group C. The linear regression data showed the relation between PaCO2 and PetCO2 to be statistically significant in the Groups A2, B, and C. The values of the difference of PaCO2-PetCO2 were 22.1+/-3.26 mmHg in Group A, 33.7+/-7.21 mmHg in Group A1, 17.6+/-3.06 mmHg in Group A2, 5.3+/-1.45 mmHg in Group B, and 21.2+/-4.73 mmHg in Group C. The 95% confidence intervals of PaCO2-PetCO2 were 15.37- 28.81 mmHg in Group A, in group A1, 16.07-51.35 mmHg in group A1, 11.11-24.03 mmHg in Group A2, 2.33-8.31 mmHg in Group B, and 10.03-32.42 mmHg in Group C. CONCLUSION: In patients with chronic pulmonary disease, who are endotracheally intubated for assisted ventilation, the PetCO2 do not reflect the PaCO2 and also the value of PaCO2-PetCO2 is not a good parameter for determining pathological status. However, in patients with acute cardiopulmonary disease and during cardiopulmonary resusciatation, the PetCO2 does not reflect the quantitative value of PaCO2, but may be used in predicting the tendency of PaCO2 to increase. In endotracheally intubated patients with extracardiopulmonary cause, PetCO 2 reflects the quantitative index of PaCO2 and the value of PaCO2-PetCO2 may be a good index for monitoring pathological conditions.
Carbon Dioxide ; Critical Illness* ; Emergencies ; Gases ; Heart Arrest ; Humans ; Korea ; Linear Models ; Lung Diseases ; Metabolism ; Prospective Studies ; Pulmonary Circulation ; Respiratory Insufficiency ; Ventilation ; Vital Signs