다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

The replacement of fossil resources that currently provide more than 90% of our energy needs and feedstocks of the chemical industry in combination with reduced emission of carbon dioxide is one of the most pressing challenges of mankind. Biomass as a globally available resource has been proposed as an alternative feedstock for production of basic building blocks, which could partially or even fully replace the currently utilized fossil-based ones in well-established chemical processes. The destruction of lignocellulosic feed followed by oxygen removal from its cellulose and hemicellulose content by catalytic processes results in the formation of initial platform chemicals (IPCs). However, their sustainable production strongly depends on the availability of resources, their efficient or even industrially viable conversion processes, and replenishment time of feedstocks. Herein, we overview recent advances and developments in catalytic transformations of the carbohydrate content of lignocellulosic biomass ...

Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability

In the context of climate change and the depletion of fossil fuels, there is a great need for alternatives to petroleum in the transport sector. This review provides an overview of the production of second generation bioethanol, which is distinguished from the first generation and subsequent generations of biofuels by its use of lignocellulosic biomass as raw material. The structural components of the lignocellulosic biomass such as cellulose, hemicellulose and lignin, are presented along with technological unit steps including pretreatment, enzymatic hydrolysis, fermentation, distillation and dehydration. The purpose of the pretreatment step is to increase the surface area of carbohydrate available for enzymatic saccharification, while minimizing the content of inhibitors. Performing the enzymatic hydrolysis releases fermentable sugars, which are converted by microbial catalysts into ethanol. The hydrolysates obtained after the pretreatment and enzymatic hydrolysis contain a wide spectrum of sugars, predominantly glucose and xylose. Genetically engineered microorganisms are therefore needed to carry out co-fermentation. The excess of harmful inhibitors in the hydrolysate, such as weak organic acids, furan derivatives and phenol components, can be removed by detoxification before fermentation. Effective saccharification further requires using exogenous hemicellulases and cellulolytic enzymes. Conventional species of distiller's yeast are unable to ferment pentoses into ethanol, and only a very few natural microorganisms, including yeast species like Candida shehatae, Pichia (Scheffersomyces) stipitis, and Pachysolen tannophilus, metabolize xylose to ethanol. Enzymatic hydrolysis and fermentation can be performed in a number of ways: by separate saccharification and fermentation, simultaneous saccharification and fermentation or consolidated bioprocessing. Pentose-fermenting microorganisms can be obtained through genetic engineering, by introducing xylose-encoding genes into metabolism of a selected microorganism to optimize its use of xylose accumulated in the hydrolysate.

/pdf/review-of-second-generation-bioethanol-production-from-4xojwq49lm.pdf

Review of Second Generation Bioethanol Production from Residual Biomass

Application of nanoparticles in biofuels: an overview

Bioethanol has been identified as the mostly used biofuel worldwide since it significantly contributes to the reduction of crude oil consumption and environmental pollution. It can be produced from various types of feedstocks such as sucrose, starch, lignocellulosic and algal biomass through fermentation process by microorganisms. Compared to other types of microoganisms, yeasts especially Saccharomyces cerevisiae is the common microbes employed in ethanol production due to its high ethanol productivity, high ethanol tolerance and ability of fermenting wide range of sugars. However, there are some challenges in yeast fermentation which inhibit ethanol production such as high temperature, high ethanol concentration and the ability to ferment pentose sugars. Various types of yeast strains have been used in fermentation for ethanol production including hybrid, recombinant and wild-type yeasts. Yeasts can directly ferment simple sugars into ethanol while other type of feedstocks must be converted to fermentable sugars before it can be fermented to ethanol. The common processes involves in ethanol production are pretreatment, hydrolysis and fermentation. Production of bioethanol during fermentation depends on several factors such as temperature, sugar concentration, pH, fermentation time, agitation rate, and inoculum size. The efficiency and productivity of ethanol can be enhanced by immobilizing the yeast cells. This review highlights the different types of yeast strains, fermentation process, factors affecting bioethanol production and immobilization of yeasts for better bioethanol production.

https://cyberleninka.org/article/n/143136.pdf

Yeasts in sustainable bioethanol production: A review.

Microlgae can serve as an excellent feedstock for bioethanol production. The microalgae cells of Chlorella were cultivated and acid hydrolyzed to extract the glucose content in the cells. Production of bioethanol was achieved by fermentation process with the use of yeast Saccharomyces cerevisiae. The bioethanol content was determined by gas chromatography–mass spectrometry (GC-MS). The effect of different parameters such as sulphuric acid concentration, temperature and time on acid hydrolysis was studied. The maximum glucose concentration of 5.382 ± 0.063 g/l was obtained with the conditions of 2.0 M sulphuric acid, 30 °C and 30 min of incubation time. On the other hand, the highest ethanol concentration of 1.126 g/l was obtained with 15% v/v yeast inoculum concentration. Meanwhile, the bioethanol production reached its maximum after 24 h with ethanol concentration and yield of 1.020 g/l and 0.190 g/g glucose, respectively.

Microalgae Chlorella as a Sustainable Feedstock for Bioethanol Production

Several contaminant that present in the river able to be removed through the physical and chemical approach. However, the efficiency is still low especially to remediate the dissolved compound such pesticides, drug and heavy metal. Nowadays, river rehabilitation using a biological approach known as bioremediation gets a great attention as the treatment processes are environmentally friendly, low cost, easily to handle and portable. Moreover, the result is highly satisfactory and at the same time no cause harm to the society. This mini-review highlights the introduction application of bioremediation to clean the contaminated environment, especially river. The advantages and disadvantages were also will be discussed

Bioremediation of Hydrocarbon: a mini review

Stingless bees harbor lactic acid bacteria (LAB) which possesses multiple beneficial properties. However, there is no report on LAB in stingless bee from Sabah and their products. This study aimed ...

https://www.tandfonline.com/doi/pdf/10.1080/10942912.2021.1900238

Isolation and characterization of lactic acid bacteria from Sabah (North Borneo) stingless bees for probiotic and food applications

Habitat disturbance and excessive collection of wild orchids from their natural habitat have threatened many orchids species at risk of extinction. In this study, the in vitro regeneration protocol for Macodes limii, a jewel orchid endemic to Sabah was established. The effects of explant source and plant growth regulators (PGRs) including naphthaleneacetic acid, picloram, 2,4-dichlorophenoxyacetic acid, 6-benzylaminopurine, kinetin, and thidiazuron on the in vitro regeneration capacity of M. limii plantlets were examined. Both factors showed a significant interaction in promoting axillary shoot formation. Nodal explants from the third and fourth positions cultured with 1.0 mg/L TDZ, induced 95% of shoot regeneration, with an average of three shoots/explant (1.6–1.8 cm of shoot length) after 90 days of culture. The well-developed plantlets went through an acclimatization phase for 60 days with a 60% of survival rate. An inter simple sequence repeat (ISSR) marker analysis confirmed the genetic stability of the in vitro regenerated plants to the mother plant. The successfully acclimatized plantlets were finally transferred to Poring Orchid Conservation Centre for reintroduction. The established protocol provides the means for large-scale production of this endemic jewel orchid, as well as a basis for further research aimed at the conservation and genetic improvement of this plant.

/pdf/establishment-of-in-vitro-regeneration-protocol-for-sabahs-2r39lixw.pdf

Ainol Azifa Mohd Faik

Papers

Yeasts in sustainable bioethanol production: A review.

Microalgae Chlorella as a Sustainable Feedstock for Bioethanol Production

Bioremediation of Hydrocarbon: a mini review

Isolation and characterization of lactic acid bacteria from Sabah (North Borneo) stingless bees for probiotic and food applications

Establishment of In Vitro Regeneration Protocol for Sabah’s Jewel Orchid, Macodes limii J.J. Wood & A.L. Lamb