Aran Incharoensakdi - Academia.edu (original) (raw)

Papers by Aran Incharoensakdi

Journal of applied phycology, May 15, 2024

Plant Physiology and Biochemistry, Oct 1, 2017

The intracellular polyamine contents are regulated not only by polyamine biosynthesis and transpo... more The intracellular polyamine contents are regulated not only by polyamine biosynthesis and transport but also by polyamine degradation catalyzed by copper-dependent amine oxidase (DAO) and FAD-dependent polyamine oxidase (PAO). The genome sequence of Synechocystis sp. PCC 6803 reveals the presence of at least one putative polyamine oxidase gene, slr5093. The open reading frame of slr5093 encoding Synechocystis polyamine oxidase (SynPAO, E.C. 1.5.3.17) was expressed in Escherichia coli. The purified recombinant enzyme had the characteristic absorption spectrum of a flavoprotein with absorbance peaks at 380 and 450 nm. The optimum pH and temperature for the oxidation of both spermidine and spermine are 8.5 and 30 °C, respectively. The enzyme catalyzed the conversion of spermine and spermidine to spermidine and putrescine, respectively, with higher catalytic efficiency when spermine served as substrate. These results suggest that SynPAO is a polyamine oxidase involved in a polyamine back-conversion pathway. Based on the structural analysis, Gln94, Tyr403 and Thr440 in SynPAO are predicted to be important residues in the active site.

Fuel, Feb 1, 2022

Lignocellulosic biomass (LCB) is expected to play a significant role in achieving the goal of bio... more Lignocellulosic biomass (LCB) is expected to play a significant role in achieving the goal of biomass-to-bioenergy conversion due to its wide distribution and low price. Acidogenic dark fermentation of LCB is a promising approach to the sustainable production of biohydrogen (bioH 2) from this valuable substrate. Because of its inherent recalcitrance, LCB requires pretreatment to increase its digestibility and enable its improved utilization. Intense thermochemical pretreatments solubilize the lignin and hemicellulose and lead to the formation of a variety of inhibitory byproducts, such as short-chain carboxylic acids, furfural, 5-hydroxymethylfurfural (5-HMF), vanillin, and syringaldehyde, which interfere with the physiological and metabolic functions of dark fermentative microbiota, thus inhibiting bioH 2 production. To offset the negative impacts of these inhibitors on bioH 2 production, approaches to detoxify lignocellulosic hydrolysates have been considered. This review comprehensively discusses the generation of lignocellulosic inhibitory byproducts in commonly used, contemporary pretreatment regimens and their inhibitory effects on dark fermentative H 2 production. Furthermore, the mechanisms of inhibiting H 2 producing bacteria and their effects on bacterial community dynamics in mixed cultures are reviewed. State-of-the-art strategies for detoxifying pretreated LCB are discussed. The selection of desirable alternative lignocellulose pretreatment strategies that produce less or no inhibitory byproducts are highlighted. Finally, this review discusses the economic aspects of bioH 2 production from LCB, considering the pretreatment and detoxification process. Given the limitations of previous studies, future research for developing cost-effective strategies to overcome byproduct inhibition during dark fermentation of pretreated LCB are suggested.

Bioresource Technology, Feb 1, 2018

BACKGROUND: The novelty of this work is the estimation of the fuel properties of biodiesel, a com... more BACKGROUND: The novelty of this work is the estimation of the fuel properties of biodiesel, a comparison study with conventional sources of biodiesel commonly used as feedstock, and an investigation for meeting the requirements of the standard specifications for this fuel produced by six strains of microalgae (three cyanobacteria, two green algae and one diatom), cultivated photosynthetically in a bubble column photobioreactor. Lipid productivity and biofuel quality were the criteria for species selection. RESULTS: Chlorella vulgaris was found to be the best strain for use as a feedstock for biodiesel production and for this specie, a carbon dioxide sequestration rate of 17.8 mg L −1 min −1 , a biomass productivity of 20.1 mg L −1 h −1 , a lipid content of 27.0% and a lipid productivity of 5.3 mg L −1 h −1 were obtained. Qualitative analysis of the fatty acid methyl esters demonstrates the predominance of saturated (43.5%) and monounsaturated (41.9%) fatty acids. The quality properties of the biodiesel were an ester content of 99.8%, a cetane number of 56.7; an iodine value of 65.0 g I 2 100 g −1 ; a degree of unsaturation of 74.1% and a cold filter plugging point of 4.5 • C. CONCLUSION: The results indicate that among the fuel properties tested, the microalgal biodiesel complies with the US Standard (ASTM 6751), European Standard (EN 14214), Brazilian National Petroleum Agency (ANP 255) and Australian Standard for biodiesel.

Plant Physiology and Biochemistry, Feb 1, 2016

Glutamate decarboxylase (GAD) (EC 4.1.1.15), an enzyme responsible for the synthesis of γ-aminobu... more Glutamate decarboxylase (GAD) (EC 4.1.1.15), an enzyme responsible for the synthesis of γ-aminobutyric acid (GABA), from Synechocystis sp. PCC6803 was cloned and overexpressed in Escherichia coli BL21(DE3). The purified enzyme was expressed as a monomeric protein with a molecular mass of 53 and 55 kDa as determined by SDS-PAGE and gel filtration chromatography, respectively. The enzyme activity was pyridoxal-5'-phosphate dependent with an optimal activity at pH 6.0 and 30 °C. The catalytic properties of this enzyme were, Km = 19.6 mM; kcat = 100.7 s(-1); and kcat/Km = 5.1 mM(-1) s(-1). The transcription levels of genes involved in nitrogen metabolism were up-regulated in the Δgad strain. The mutant showed approximately 4- and 8-fold increases in the transcript levels of kgd and gabdh encoding a novel α-ketoglutarate decarboxylase and γ-aminobutanal dehydrogenase, respectively. Overall results suggested that in Synechocystis lacking a functional GAD, the γ-aminobutanal dehydrogenase might serve as an alternative catalytic pathway for GABA synthesis.

Fuel, Apr 1, 2018

The present study focuses on the biorefinery approach of integrated production of bioethanol and ... more The present study focuses on the biorefinery approach of integrated production of bioethanol and biodiesel from microalgae feedstock. Various pretreatment methods were used to determine the maximum recovery of sugars from Scenedesmus sp. The total sugar yield of 93% was obtained when the biomass was pretreated by acid hydrolysis. The hydrolysate produced 86% of ethanol (theoretical yield) after the fermentation using Saccharomyces cerevisiae. Enzyme catalyzed direct transesterification of the biomass was performed using dimethyl carbonate as a solvent and the maximum yield of 92% methyl ester, 1.86% glycerol carbonate and 4.93% glycerol dicarbonate was achieved. The integrated process of bioethanol and biodiesel production was optimally achieved when direct transesterification was done first followed by ethanol fermentation yielding 92 and 93% of methyl ester and ethanol, respectively.

Journal of Biotechnology, Dec 1, 2022

Journal of Applied Phycology, May 22, 2021

Under an adequate supply of nitrogen (N) and phosphorus (P), the cyanobacterium Synechocystis sp.... more Under an adequate supply of nitrogen (N) and phosphorus (P), the cyanobacterium Synechocystis sp. PCC 6803 produced a high biomass yield but with a low storage level of glycogen and poly(3-hydroxybutyrate) (PHB). In contrast, deprivation of N or P stimulated accumulation of glycogen and PHB, but reduced biomass yield. In addition, deprivation of N or P had no apparent effect on total lipid accumulation. Here, we examined how partial supply of N or P has effects on the biomass yield and production of glycogen, PHB, and lipids. The N or P supply in the culture media was orderly decreased from 100% (set according to the standard BG11 medium) to 50, 35, 20, 10, and 0%. A 100% supply of both N and P produced biomass of up to 1.4 g L−1, while a 35–50% N supply slightly reduced the biomass to 1.2–1.3 g L−1, and no apparent change in the biomass was detected under a 20–50% P supply. A maximum glycogen accumulation of 51.8% (w/w dry weight; DW) was obtained under 20% P supply, while the maximum PHB storage of 6.3% (w/w DW) was obtained with 10% P supply. Lipid accumulation peaked at 12.7% (w/w DW) under 0% P supply. The maximal co-production of these three bioproducts was obtained under 20% P supply at 765 mg L−1 which is the sum of 72 mg L−1 PHB (corresponding to 5.1% w/w DW PHB), 618 mg L−1 glycogen (43.8% w/w DW glycogen), and 75 mg L−1 lipid (5.3% w/w DW lipid) from the total biomass production of 1.4 g L−1. The glycogen production (618 mg L−1) was higher than those previously reported for Synechocystis. The results indicated that a proper adjustment of initial N and P supplies in the culture is crucial for maximal production of these three bioproducts by Synechocystis.

Plant Science, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Agricultural and Food Chemistry, Nov 22, 2019

Photosynthetic cyanobacteria can fix CO2 and utilize it as the sole carbon source for cell growth... more Photosynthetic cyanobacteria can fix CO2 and utilize it as the sole carbon source for cell growth and production of biochemicals. Here, we metabolically engineered Synechococcus elongatus PCC 7942 for enhanced production of α-farnesene by optimizing the ribosome binding site (RBS) of the codon-optimized farnesene synthase gene. The production of α-farnesene was found to be enhanced in strains with a low translation initiation rate, resulting in α-farnesene production (0.57 mg/L/d). Using the RBS-variants and random mutations, we performed fluorescence-based analysis of cells grown in 96-well culture plates in order to screen the α-farnesene producing strains but could not improve the titers of the RBS-optimized strains. However, evolutionary engineering of the RBS-optimized strains resulted in a 2-fold increase in α-farnesene production (1.2 mg/L/d) compared to the previous study. Therefore, combining metabolic and evolutionary engineering might be helpful for enhancing the cellular fitness of cyanobacteria for the production of target chemicals.

Biotechnology and Bioprocess Engineering, Nov 23, 2020

Enzyme and microbial technology, Oct 1, 2020

Fuel, Mar 1, 2017

h i g h l i g h t s Ultrasound can improve the efficiency of lipase catalysed direct transesterif... more h i g h l i g h t s Ultrasound can improve the efficiency of lipase catalysed direct transesterification. DMC can be simultaneously used as both extraction and transesterification reagent. The complete reaction time is reduced from 36 h to 4 h with a higher yield. Simultaneous glycerol carbonate production is achieved during transesterification.

Plant and Cell Physiology, 2001

CRC Press eBooks, Apr 2, 2021

Asia-Pacific Journal of Science and Technology, Jul 15, 2016

Green algae are able to convert the unlimited sunlight energy to produce hydrogen via photosynthe... more Green algae are able to convert the unlimited sunlight energy to produce hydrogen via photosynthesis. In seawater, several kinds of marine microalgae are widespread and abundant and have been shown to tolerate and survive under the extreme salt concentrations. This work aimed to study the screening of high H 2 producing marine green algal strains isolated from the Gulf of Thailand and the Andaman Sea, and the selection of the highest H 2 producing strain. Its H 2 production was investigated under photoheterotrophic cultivation. The result revealed that among 20 marine green algal strains, the green alga Chlorella sp. LSD-W2 gave the highest H 2 production rate in both light and dark anaerobic conditions. During photoheterotrophic cultivation Chlorella sp. LSD-W2 was rapidly grown in TAP (Tris-Acetate-Phosphate) medium and reached the stationary growth phase after 36 h of cultivation. The highest photohydrogen production rate was found in cells incubated in NH 4 Cl-deprived TAP medium. It was approximately 20-fold higher than H 2 production rate of cells in a normal TAP medium.