The Halophilic Bacterium Paracoccus haeundaensis for the Production of Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate) from Single Carbon Sources.

The study objective was to evaluate the potential production of polyhydroxyalkanoates (PHAs), a biodegradable plastic material, by Paracoccus haeundaensis for which PHA production has never been reported. To identify the most effective nitrogen-limited culture conditions for PHAs production from this bacterium, batch fermentation using glucose concentrations ranging from 4 g l-1 to 20 g l-1 with a fixed ammonium concentration of 0.5 g l-1 was carried out at 30°C and pH 8.0. A glucose supplement of 12 g l-1 produced the highest PHA concentration (1.6 g l-1) and PHA content (0.63 g g-1) thereby identifying the optimal condition for PHA production from this bacterium. Gas chromatography-mass spectrometry analysis suggests that P. haeundaensis mostly produced copolymer types of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] from glucose concentrations at 12 g l-1 or higher under the nitrogen-limited conditions. When several other single carbon sources were evaluated for the most efficient PHA production, fructose provided the highest biomass (2.8 g l-1), and PHAs (1.29 g l-1) concentrations. Results indicated that this bacterium mostly produced the copolymers P(3HB-co-3HV) from single carbon sources composing a range of 93-98% of 3-hydroxybutyrate and 2-7% of 3-hydroxyvalerate, whereas mannose-supplemented conditions produced the only homopolymer type of P(3HB). However, when propionic acid as a secondary carbon source were supplemented into the media, P. haeundaensis produced the copolymer P(3HB-co-3HV), composed of a 50% maximum monomeric unit of 3-hydroxyvaleric acid (3HV). However, as the concentration of propionic acid increased, cell biomass and PHAs concentrations substantially decreased due to cell toxicity.

Functional use of CO2 to mitigate the formation of bisphenol A in catalytic pyrolysis of polycarbonate.

The growing consumption of plastic materials has increased hazardous threats to all environmental media, since current plastic waste management methods release microplastics and toxic chemicals. As such, massive generation of plastic derived pollutants leads to significant public health and environmental problems. In this work, an environmentally sound method for valorization of plastic waste is suggested. In detail, pyrolysis of polycarbonate-containing plastic waste such as automotive headlight housing (AHH) was carried out using CO2 as a co-reactant. AHH was chosen as it discharges bisphenol A (BPA) and aromatic compounds. Under CO2 condition, emissions of BPA and its derivatives were suppressed by 14.5% due to gas phase reactions (GPRs) with CO2. Nevertheless, reaction kinetics for GPRs was not significant. To impart the GPRs, catalytic pyrolysis was done using Ni and Co-based catalysts. During catalytic pyrolysis, syngas production was more than tenfold up comparing to pyrolysis without catalyst. The expedited GPRs over catalysts resulted in the enhanced syngas formation. Total concentration of the toxic chemicals from CO2-assisted catalytic pyrolysis of AHH decreased by 86.1% and 66.7% over Ni and Co catalysts, comparing to those from N2 environment.

Valorization of aflatoxin contaminated peanut into biodiesel through non-catalytic transesterification.

Aflatoxins (AFs) are the extremely hazardous metabolites (carcinogens) that are sporadically observed in crops, and these toxic chemicals are indeed lethal to the health of living organisms including human beings. Thus, AF contaminated food waste needs to be disposed as an environmentally benign way, not releasing it into the environment. This study offered a sustainable disposal and valorization platform for AF contaminated food. Peanut was used as a model food waste, because AF is readily appeared in the peanut during its harvesting, cultivation, storage, transportation process. As the valorization platform, non-catalytic transesterification of AF contaminated peanut was employed to convert it to biodiesel (BD). From the process, lipid in AF contaminated peanut is converted into BD (95.2 wt% yield) at 365°C for 1 min. Since the boiling points of BD and AF are significantly different, this process could also resolve the separation problem of AF (180 °C) from BD (≥ 330 °C) during the transesterification reaction. As a comparison study, alkali-catalyzed reaction was done. The alkali-catalyzed one required a pretreatment process to extract peanut oil for transesterification. The highest yield was 67.8 wt% yield after 6 h of reaction at 65 °C.

Valorization of carbon dioxide and waste (Derived from the site of Eutrophication) into syngas using a catalytic thermo-chemical platform.

Global warming increases a chance of eutrophication, and such fact offers that unhygienic organic waste materials (OWMs) in water must be treated. Hence, this study laid emphasis on the thermal-chemical (pyrolysis) process to establish a rapid valorization platform for OWMs. Indeed, OWMs were collected from the eutrophication site, and OWMs were mainly comprised of lignocellulosic biomass, microalgae (cyanobacteria) and the diverse types of bacteria (commonly observed from livestock waste). In an attempt to offer more sustainable valorization route for OWMs, CO2 was used as a raw material in pyrolysis process. From the CO2-assisted pyrolysis, the conversion of CO2 and OWMs into gaseous fuel (CO) was observed. A cheap Ni-based catalyst was used in pyrolysis of OWMs as a strategic practice to promote conversion of CO2 into CO. Indeed, syngas production (38 %) was enhanced from catalytic pyrolysis over Ni/SiO2 under CO2 condition as compared to inert condition (N2).

Pikeienuella piscinae gen. nov., sp. nov., a novel genus in the family Rhodobacteraceae.

A novel bacterium, designated strain RR4-56T, was isolated from a biofilter of a seawater recirculating aquaculture system. The 16S rRNA gene sequence analysis showed that the isolate was closely related to Halovulum dunhuangense YYQ-30T (92.6%), Albimonas donghaensis DS2T (91.3%), Pontivivens insulae GYSW-23T (91.3%), and Monaibacterium marinum C7T (90.9%), belonging to the family Rhodobacteraceae. The strain was aerobic, Gram-negative, rod-shaped, oxidase-positive, and catalase-negative. Its optimum temperature, pH, and salinity for growth were 25-30°C, pH 8.5, and 2-3% NaCl (w/v), respectively. Its growth occurred at 15-35°C, pH 5.0-9.5, and 0-7% NaCl (w/v). It contained ubiquinone-10 (Q-10), a respiratory quinone, and the major cellular fatty acids were 11-methyl C18:1 ω7c (31.9%), C18:1 ω6c (30.4%), and C19:0 cyclo ω8c (16.1%). The polar lipids present in the strain were phosphatidylglycerol, an unidentified phospholipid, and an unidentified aminolipid. The strain had one 4,373,045 bp circular chromosome with G + C contents of 65.9 mol% including 4,169 genes, 4,118 coding sequences (CDSs), 3 rRNAs, and 45 tRNAs. Genome annotation predicted some gene clusters related to the degradation of several types of organic matter such as protocatechuate, catechol, and phthalate. Based on the polyphasic characteristics, RR4-56T represents a novel genus and species in the family Rhodobacteraceae, for which the name Pikeienuella piscinae gen. nov., sp. nov. was proposed. The type strain is RR4-56T (= KCTC 52648T = DSM 107918T).

Biodiesel synthesis from swine manure.

This study demonstrates that the biodiesel (BD) from swine manure (SM) could be a promising way for large scale generation of biofuel. Also, the economic and environmental benefits of SM derived BD were evaluated. Transesterification of lipid contents extracted from the collected SM had low BD yield (14.2 wt%) using H2SO4 catalyst due to high acid value and impurities. However, thermo-chemical non-catalytic transesterification with a porous material showed 94.7 wt% yield of BD from the lipid in SM. Considering the current population of swine, the annual production of BD from SM was estimated. The SM derived BD could cover 19.7 and 46.8 wt% of BD currently produced in both Korea and the USA with the economic benefits of up to $96 million and $2.1 billion, respectively. The proposed approach also can save vast arable lands needed to cultivate oil-bearing feedstocks for BD production.

Salaquimonas pukyongi gen. nov., sp. nov., a novel bacterium within the family Phyllobacteriaceae.

A novel aerobic, Gram-negative bacterial strain, RR3-28T, was isolated from a seawater recirculating aquaculture system in Busan, Republic of Korea. Cells were rod-shaped, non-motile, oxidase-positive, catalase-negative and grew optimally at 25-30 °C, pH 8.5 and 3 % (w/v) NaCl. Based on the results of phylogenetic analysis, strain RR3-28T was most closely related to Zhengella mangrovi X9-2-2T within the family Phyllobacteriaceae with 95.97 % 16S rRNA gene sequence similarity. The major cellular fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c, 71.1 %) and 11-methyl C18 : 1ω7c (14.4 %). The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine and unidentified aminolipids. The predominant quinone was ubiquinone Q-10 and the DNA G+C content was 58.6 mol%. On the basis of its phenotypic and genotypic characteristics, strain RR3-28T represents a novel genus and species belonging to the family Phyllobacteriaceae, for which the name Salaquimonas pukyongi gen. nov., sp. nov. is proposed. The type strain of the species is RR3-28T (=KCTC 52649T=DSM 107947T).

Production of bioplastic through food waste valorization.

The tremendous amount of food waste from diverse sources is an environmental burden if disposed of inappropriately. Thus, implementation of a biorefinery platform for food waste is an ideal option to pursue (e.g., production of value-added products while reducing the volume of waste). The adoption of such a process is expected to reduce the production cost of biodegradable plastics (e.g., compared to conventional routes of production using overpriced pure substrates (e.g., glucose)). This review focuses on current technologies for the production of polyhydroxyalkanoates (PHA) from food waste. Technical details were also described to offer clear insights into diverse pretreatments for preparation of raw materials for the actual production of bioplastic (from food wastes). In this respect, particular attention was paid to fermentation technologies based on pure and mixed cultures. A clear description on the chemical modification of starch, cellulose, chitin, and caprolactone is also provided with a number of case studies (covering PHA-based products) along with a discussion on the prospects of food waste valorization approaches and their economic/technical viability.

Effect of biochars pyrolyzed in N2 and CO2, and feedstock on microbial community in metal(loid)s contaminated soils.

Little is known about the effects of applying amendments on soil for immobilizing metal(loid)s on the soil microbial community. Alterations in the microbial community were examined after incubation of treated contaminated soils. One soil was contaminated with Pb and As, a second soil with Cd and Zn. Red pepper stalk (RPS) and biochars produced from RPS in either N2 atmosphere (RPSN) or CO2 atmosphere (RPSC) were applied at a rate of 2.5% to the two soils and incubated for 30 days. Bacterial communities of control and treated soils were characterized by sequencing 16S rRNA genes using the Illumina MiSeq sequencing. In both soils, bacterial richness increased in the amended soils, though somewhat differently between the treatments. Evenness values decreased significantly, and the final overall diversities were reduced. The neutralization of pH, reduced available concentrations of Pb or Cd, and supplementation of available carbon and surface area could be possible factors affecting the community changes. Biochar amendments caused the soil bacterial communities to become more similar than those in the not amended soils. The bacterial community structures at the phylum and genus levels showed that amendment addition might restore the normal bacterial community of soils, and cause soil bacterial communities in contaminated soils to normalize and stabilize.

Fatal cardiac tamponade that developed in the post-anesthesia care unit: a rare complication after lung lobectomy / Tamponamento cardíaco fatal desencadeado na sala de recuperação pós-anestésica: uma complicação rara após lobectomia pulmonar

Abstract Background and objectives: Cardiac tamponade is potentially fatal medical condition, which rarely occurs as a complication of lung lobectomy. We present the first case of cardiac tamponade to develop in a Post-Anesthesia Care Unit following a lung lobectomy. Case report: A 54-year-old man with pulmonary squamous cell carcinoma underwent an apparently uncomplicated lung lobectomy. His hemodynamics was unremarkable throughout the surgery and initially in the Post-Anesthesia Care Unit. However, after 5 min in the Post-Anesthesia Care Unit, he suddenly became hypotensive and dyspneic. He responded poorly to inotropics and fluid resuscitation. Transesophageal echocardiography conducted by an anesthesiologist who suspected a cardiac etiology revealed a pericardial effusion compressing the heart. After a failed attempt of pericardiocentesis, an emergency pericardial window operation was performed. The patient improved dramatically once the heart was decompressed. Conclusion: Since cardiac tamponade is generally not suspected as a cause of hemodynamic instability after a lung lobectomy, as it was in this case, a misdiagnosis of the patient's condition may have led to improper management resulting in death. As anesthesiologists are often involved in the initial resuscitation of morbid patients in Post-Anesthesia Care Units, their acquaintance with various postoperative complications and competence in echocardiography for assessing cardiac problems may contribute to patient survival.

Resumo Justificativa e objetivos: O tamponamento cardíaco é uma condição médica potencialmente fatal, cuja ocorrência como uma complicação da lobectomia pulmonar é muito rara. Apresentamos o primeiro caso de tamponamento cardíaco desencadeado na sala de recuperação pós-anestésica (SRPA) após uma lobectomia pulmonar. Relato de caso: Paciente do sexo masculino, 54 anos, com carcinoma de células escamosas pulmonares, submetido à lobectomia pulmonar aparentemente sem complicações. Sua hemodinâmica não apresentou alteração durante toda a cirurgia e também inicialmente na sala de recuperação pós-anestésica. Porém, após cinco minutos na SRPA, o paciente apresentou hipotensão e dispneia de forma repentina e respondeu mal ao inotrópico e à reanimação hídrica. Uma ecocardiografia transesofágica feita por um anestesiologista que suspeitou de etiologia cardíaca revelou um derrame pericárdico que comprimia o coração. Após tentativa malsucedida de pericardiocentese, foi feita uma janela pericárdica de emergência. O paciente apresentou melhoria dramática com a descompressão do coração. Conclusão: Como o tamponamento cardíaco geralmente não é suspeito como causa de instabilidade hemodinâmica após lobectomia pulmonar, como ocorreu neste caso, um diagnóstico errado da condição do paciente poderia ter levado a um manejo inadequado, que resultaria em morte. Como os anestesiologistas estão frequentemente envolvidos na reanimação inicial de pacientes debilitados em salas de recuperação pós-anestésica, seu conhecimento de várias complicações pós-operatórias e competência na ecocardiografia para avaliar problemas cardíacos podem contribuir para a sobrevivência do paciente.

[Fatal cardiac tamponade that developed in the post-anesthesia care unit: a rare complication after lung lobectomy]. / Tamponamento cardíaco fatal desencadeado na sala de recuperação pós-anestésica: uma complicação rara após lobectomia pulmonar.

BACKGROUND AND OBJECTIVES: Cardiac tamponade is potentially fatal medical condition, which rarely occurs as a complication of lung lobectomy. We present the first case of cardiac tamponade to develop in a Post-Anesthesia Care Unit following a lung lobectomy. CASE REPORT: A 54-year-old man with pulmonary squamous cell carcinoma underwent an apparently uncomplicated lung lobectomy. His hemodynamics was unremarkable throughout the surgery and initially in the Post-Anesthesia Care Unit. However, after 5min in the Post-Anesthesia Care Unit, he suddenly became hypotensive and dyspneic. He responded poorly to inotropics and fluid resuscitation. Transesophageal echocardiography conducted by an anesthesiologist who suspected a cardiac etiology revealed a pericardial effusion compressing the heart. After a failed attempt of pericardiocentesis, an emergency pericardial window operation was performed. The patient improved dramatically once the heart was decompressed. CONCLUSION: Since cardiac tamponade is generally not suspected as a cause of hemodynamic instability after a lung lobectomy, as it was in this case, a misdiagnosis of the patient's condition may have led to improper management resulting in death. As anesthesiologists are often involved in the initial resuscitation of morbid patients in Post-Anesthesia Care Units, their acquaintance with various postoperative complications and competence in echocardiography for assessing cardiac problems may contribute to patient survival.

Preventative effect of ketamine on post-surgical hyperalgesia induced at a body part remote from the surgical site.

BACKGROUND: It is known that pain hypersensitivity can be induced at a body part remote from a surgical site (tertiary hyperalgesia), leading to patient discomfort. Nevertheless, no reported study to date has investigated methods to attenuate such tertiary hyperalgesia. Ketamine is known to modulate hyperalgesia induced by central sensitization. Thus, we investigated whether intraoperative administration of ketamine could decrease post-surgical tertiary hyperalgesia in patients undergoing a laparoscopic hysterectomy. METHODS: In total 46 patients were studied. Ketamine (1 mg/kg IV and 0.5 mg/kg/h or the same volume of 0.9% saline) was administered during surgery in the ketamine and control groups, respectively. The mechanical pain threshold was measured on the patients' dominant palm before and 24 hours after the surgery to evaluate hyperalgesia. RESULTS: The change in mechanical pain threshold over time (preoperative and postoperative) differed between the groups, with a lower postoperative threshold in the control group (118.6±170.5 vs. 419.2±233; P=0.015). The postoperative visual analogue scale score at rest was lower in the ketamine group (22±16 vs. 13±9; P=0.02). Visual analogue scale scores during deep breathing, consumption of analgesia and antiemetics, and the incidence of dizziness did not differ significantly between the groups (P>0.05). CONCLUSIONS: These results suggest that the intraoperative administration of ketamine may decrease post-surgical hyperalgesia developing at a region remote from the surgical site.

The effect of humidified heated breathing circuit on core body temperature in perioperative hypothermia during thyroid surgery.

Purpose: During general anesthesia, human body easily reaches a hypothermic state, which is mainly caused by heat redistribution. Most studies suggested that humidified heated breathing circuits (HHBC) have little influence on maintenance of the core temperature during early phase of anesthesia. This study was aimed at examining heat preservation effect with HHBC in case of undergoing surgery with less exposure of surgical fields and short surgical duration. Methods: Patients aged 19 to 70 yr - old, ASA-PS I or II who were scheduled for elective thyroidectomy were assigned and divided to the group using HHBC (G1) and the group using conventional circuit (G2) by random allocation. During operation, core, skin, and room temperatures were measured every 5minutes by specific thermometer. Results: G1 was decreased by a lesser extent than G2 in core temperature, apparently higher at 30 and 60 minutes after induction. Skin and room temperatures showed no differences between the two groups (p>0.05). Consequently, we confirmed HHBC efficiently prevented a decrease in core temperature during early period in small operation which has difficulty in preparing warming devices or environments were not usually considered. Conclusions: This study showed that HHBC influences heat redistribution in early period of operation and can lessen the magnitude of the decrease in core body temperature. Therefore, it can be applied efficiently for other active warming devices in mild hypothermia.

The role of algae and cyanobacteria in the production and release of odorants in water.

This review covers literatures pertaining to algal and cyanobacterial odor problems that have been published over the last five decades. Proper evaluation of algal and cyanobacterial odors may help establish removal strategies for hazardous metabolites while enhancing the recyclability of water. A bloom of microalgae is a sign of an anthropogenic disturbance in aquatic systems and can lead to diverse changes in ecosystems along with increased production of odorants. In general, because algal and cyanobacterial odors vary in chemistry and intensity according to blooming pattern, it is necessary to learn more about the related factors and processes (e.g., changes due to differences in taxa). This necessitates systematic and transdisciplinary approaches that require the cooperation of chemists, biologists, engineers, and policy makers.

Industrial robustness linked to the gluconolactonase from Zymomonas mobilis.

The physiological characteristics and the potential gluconolactone production of the gluconolactonase-deficient strain, Zymomonas mobilis ZM4 gnlΔ, were investigated via growth inhibitory assay and biotransformation of glucose and fructose into gluconolactone and sorbitol, respectively. The results of ethanol fermentation studies performed in the presence of high concentration of glucose (>200 g l-1) under fermentative or aerobic conditions indicated that a significant reduction of volumetric ethanol productivity from the strain of ZM4 gnlΔ was noticeable due to the reduced rates of specific growth, sugar uptake, and biomass yield as compared with those of the parental strain ZM4. The biotransformation prepared at pH 6.0 using the permeabilized cell indicated that gluconic acid from ZM4 gnlΔ was still produced as a major product (67 g l-1) together with sorbitol (65 g l-1) rather than gluconolactone after 24 h. Only small amount of gluconolactone was transiently overproduced up to 9 g l-1, but at the end of biotransformation, all gluconolactone were oxidized into gluconic acid. This indicated that autolysis of gluconolactone at the pH led to such results despite under gluconolactonase inactivation conditions. The physiological characteristics of ZM4 gnlΔ was further investigated under various stress conditions, including suboptimal pH (3.5~6.0), temperature (25~40 °C), and presence of growth inhibitory molecules including hydrogen peroxide, ethanol, acetic acid, furfural, and so forth. The results indicated that ZM4 gnlΔ was more susceptible at high glucose concentration, low pH of 3.5, and high temperature of 40 °C and in the presence of 4 mM H2O2 comparing with ZM4. Therefore, the results were evident that gluconolactonase in Z. mobilis contributed to industrial robustness and anti-stress regulation.

Enhanced thermal destruction of toxic microalgal biomass by using CO2.

This work confirmed that dominant microalgal strain in the eutrophic site (the Han River in Korea) was Microcystis aeruginosa (M. aeruginosa) secreting toxins. Collected and dried microalgal biomass had an offensive odor due to microalgal lipid, of which the content reached up to 2±0.2wt.% of microalgal biomass (dry basis). This study has validated that the offensive odor is attributed to the C3-6 range of volatile fatty acids (VFAs), which was experimentally identified by the non-catalytic transformation of triglycerides (TGs) and free fatty acids (FFAs) in microalgal biomass into fatty acid methyl esters (FAMEs). In particular, this study mechanistically investigated the influence of CO2 in the thermal destruction (i.e., pyrolysis) of hazardous microalgal biomass in order to achieve dual purposes (i.e., thermal disposal of hazardous microalgal biomass and energy recovery). The influence of CO2 in pyrolysis of microalgal biomass was identified as 1) the enhanced thermal cracking behaviors of volatile organic compounds (VOCs) from the thermal degradation of microalgal biomass and 2) the direct gas phase reaction between CO2 and VOCs. These identified influences of CO2 in pyrolysis of microalgal biomass significantly enhanced the generation of CO: the enhanced generation of CO in the presence of CO2 was 590% at 660°C, 1260% at 690°C, and 3200% at 720°C. In addition, two identified influences of CO2 (i.e., enhanced thermal cracking and direct gas phase reaction) occurred simultaneously and independently. The identified gas phase reaction in the presence of CO2 was only initiated at temperatures higher than 500°C, which was different from the Boudouard reaction. Lastly, the experimental work justified that exploiting CO2 as a reaction medium and/or chemical feedstock will provide new technical approaches for controlling syngas ratio and in-situ air pollutant control without using catalysts.

Pyrogenic transformation of Nannochloropsis oceanica into fatty acid methyl esters without oil extraction for estimating total lipid content.

This study fundamentally investigated the pseudo-catalytic transesterification of dried Nannochloropsis oceanica into fatty acid methyl esters (FAMEs) without oil extraction, which was achieved in less than 5min via a thermo-chemical pathway. This study presented that the pseudo-catalytic transesterification reaction was achieved in the presence of silica and that its main driving force was identified as temperature: pores in silica provided the numerous reaction space like a micro-reactor, where the heterogeneous reaction was developed. The introduced FAME derivatization showed an extraordinarily high tolerance of impurities (i.e., pyrolytic products and various extractives). This study also explored the thermal cracking of FAMEs derived from N. oceanica: the thermal cracking of saturated FAMEs was invulnerable at temperatures lower than 400°C. Lastly, this study reported that N. oceanica contained 14.4wt.% of dried N. oceanica and that the introduced methylation technique could be applicable to many research fields sharing the transesterification platform.

Pyrolysis of microalgal biomass in carbon dioxide environment.

This work mechanistically investigated the influence of CO2 in the thermo-chemical process of microalgal biomass (Chlorella vulgaris and Microcystis aeruginosa) to achieve a fast virtuous cycle of carbon via recovering energy. This work experimentally justified that the influence of CO2 in pyrolysis of microalgal biomass could be initiated at temperatures higher than 530 °C, which directly led to the enhanced generation of syngas. For example, the concentration of CO from pyrolysis of M. aeruginosa increased up to ∼ 3000% at 670 °C in the presence of CO2. The identified universal influence of CO2 could be summarized by the expedited thermal cracking of VOCs evolved from microalgal biomass and by the unknown reaction between VOCs and CO2. This identified effectiveness of CO2 was different from the Boudouard reaction, which was independently occurred with dehydrogenation. Thus, microalgal biomass could be a candidate for the thermo-chemical process (pyrolysis and gasification).

Boosting the value of biodiesel byproduct by the non-catalytic transesterification of dimethyl carbonate via a continuous flow system under ambient pressure.

Transformation of coconut oil into biodiesel by using dimethyl carbonate (DMC) via a non-catalytic transesterification reaction under ambient pressure was investigated in this study. The non-catalytic transformation to biodiesel was achieved by means of a heterogeneous reaction between liquid triglycerides and gas phase DMC. The reaction was enhanced in the presence of porous material due to its intrinsic physical properties such as tortuosity and absorption/adsorption. The numerous pores in the material served as micro reaction chambers and ensured that there was enough contact time between the liquid triglycerides and the gaseous DMC, which enabled the completion of the transesterification. The highest fatty acid methyl esters (FAMEs) yield achieved was 98±0.5% within 1-2min at a temperature of 360-450°C under ambient pressure. The fast reaction rates made it possible to convert the lipid feedstock into biodiesel via a continuous flow system without the application of increased pressure. This suggested that the commonly used supercritical conditions could be avoided, resulting in huge cost benefits for biodiesel production. In addition, the high value of the byproduct from the transesterification of the lipid feedstock with DMC suggested that the production biodiesel using this method could be more economically competitive. Finally, the basic properties of biodiesel derived from the non-catalytic conversion of rapeseed oil with DMC were summarised.

Effect of carbon dioxide on the thermal degradation of lignocellulosic biomass.

Using biomass as a renewable energy source via currently available thermochemical processes (i.e., pyrolysis and gasification) is environmentally advantageous owing to its intrinsic carbon neutrality. Developing methodologies to enhance the thermal efficiency of these proven technologies is therefore imperative. This study aimed to investigate the use of CO2 as a reaction medium to increase not only thermal efficiency but also environmental benefit. The influence of CO2 on thermochemical processes at a fundamental level was experimentally validated with the main constituents of biomass (i.e., cellulose and xylan) to avoid complexities arising from the heterogeneous matrix of biomass. For instance, gaseous products including H2, CH4, and CO were substantially enhanced in the presence of CO2 because CO2 expedited thermal cracking behavior (i.e., 200-1000%). This behavior was then universally observed in our case study with real biomass (i.e., corn stover) during pyrolysis and steam gasification. However, further study is urgently needed to optimize these experimental findings.