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Author: search.filters.author.Klomklao, Sappasith

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    Ultrasonic enhancement of lipase-catalyzed transesterification for biodiesel production from used cooking oil
    (2023-06-01)
    Patchimpet, Jaran
    ;
    Zhang, Yi
    ;
    Simpson, Benjamin K.
    ;
    Rui, Xin
    ;
    Sangkharak, Kanokphorn
    This work investigated the ultrasonic irradiation-enhanced transesterification using lipase from the viscera of Nile tilapia (Oreochromis niloticus) to produce biodiesel from used cooking oil (UCO) and methanol. The effects of processing conditions such as irradiation time, ultrasonic frequency, and temperature on biodiesel yield were investigated. Results showed that the use of ultrasound decreased the reaction time from 28 to 3 h with ultrasonic frequency of 16 kHz, methanol to oil molar ratio of 4:1, lipase concentration of 30 kUnit, and reaction temperature of 40 °C. The efficacy of ultrasound was compared with conventional mechanical stirring operated at optimum conditions, and the ultrasonic irradiation coupled with stirring enhanced the transesterification with the highest yield of 97.59%. The fuel properties of the produced biodiesel in this study desirably met the recommended biodiesel standards as prescribed by EN 14214 and ASTM D 6751, suggesting the biodiesel obtained from ultrasound-assisted lipase-catalyzed transesterification of UCO with methanol is a promising alternative for conventional biodiesels and diesels. Graphical abstract: [Figure not available: see fulltext.].
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    Nanoporous Carbon from Water Hyacinth via Hydrothermal Carbonization assisted Chemical Activation for Dye adsorption
    (2022-07-01)
    Sukulbrahman, Manu
    ;
    Siraorarnroj, Siwat
    ;
    Suksai, Nattaya
    ;
    Kaewtrakulchai, Napat
    ;
    Chutipaijit, Sutee
    Nanoporous carbon was successfully prepared by hydrothermal carbonization with chemical activation using water hyacinth as a raw material. The porous carbon was produced for the adsorption of methylene blue (MB), which is an organic pollutant in wastewater from several industries. The effect of various parameters such as pH, dye concentration and adsorption period time on dye removal were studied. The highest removal efficiency of MB obtained using WH nanoporous carbon was approximately 96.8-99.9% within an adsorption time between 10 and 30 min. The dye removal capacity increased with increasing of period time during the adsorption test. Moreover, the adsorption kinetics of MB during adsorption process was explained by the Langmuir and Freundlich adsorption isotherms.
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    Thermoseparating aqueous two-phase system for lipase recovery and partitioning from Nile tilapia viscera: Biochemical properties and effect of ultrasound
    (2021-06-01)
    Patchimpet, Jaran
    ;
    Sangkharak, Kanokphorn
    ;
    Eiad-ua, Apiluck
    ;
    Klomklao, Sappasith
    Lipase from Nile tilapia (Oreochromis niloticus) viscera were partitioned and recovered using a thermoseparating aqueous two-phase system (T-ATPS). Different phase partitioning parameters, including type and concentration of salts, concentration of EOPO, NaCl addition, the EOPO phase/distilled water ratio and temperature were optimized. In the primary ATPS, lipase was satisfactorily partitioned to the EOPO-rich top phase in the optimum system composed of 20% crude enzyme, 40% EOPO 3900, 10% (NH<inf>4</inf>)<inf>2</inf>SO<inf>4</inf> and 4% NaCl. In the secondary ATPS, the optimum ratio between the EOPO-rich top phase and distilled water was 1:1 (w/w) and the optimum temperature for inducing phase separation was 60 °C. After thermoseparation, water solution containing lipase and EOPO were formed in the top and bottom phase of this step, respectively. Under the optimal partitioning condition, the yield (64.45%) and purification fold (PF: 6.30-fold) were obtained. Additionally, the lipases retained in the salt-rich bottom phase in the primary ATPS were successfully recovered from the recycling step no more than three times. The total yield of 93.59% was obtained from this separation system. The partitioned enzyme exhibited optimal activity at pH 8.5 and 40 °C and was stable at a temperature range of 0–40 °C and a pH range of 8–10. It showed high tolerance in the presence of ethanol and methanol. The effect of ultrasound on the partitioned lipase activity was also studied. The highest lipase activity was achieved when the sample was treated with ultrasound at 180 W and 24 kHz for 20 min at 40 °C, under which the activity was increased by 110.73% over the control. Therefore, the T-ATPS was found to be an attractive technique for the recovery and partial purification of lipase from Nile tilapia viscera. Also, ultrasound could obviously improve its activity.
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    Cold-adapted structural properties of trypsins from walleye pollock (Theragra chalcogramma) and Arctic cod (Boreogadus saida)
    (2011-12-01)
    Kanno, Gaku
    ;
    Kishimura, Hideki
    ;
    Yamamoto, Jun
    ;
    Ando, Seiichi
    ;
    Shimizu, Takeshi
    Complementary DNA clones encoding trypsins were isolated from pyloric ceca of cold-adapted fish, walleye pollock (Theragra chalcogramma) (WP-T) and Arctic cod (Boreogadus saida) (AC-T). The isolated full-length cDNA clones of WP-T and AC-T were 852 and 860 bp, respectively, and both cDNAs were contained an open reading frame of 726 bp. WP-T and AC-T seemed to be synthesized as preproenzyme that contains a signal peptide, an activation peptide, and a mature trypsin. Although the amino acid sequence identities of WP-T and AC-T to that of bovine trypsin were 64 and 63%, respectively, they completely conserved the structural features for catalytic function of trypsin. On the other hand, WP-T and AC-T possessed the four Met residues (Met135, Met145, Met175 and Met242) in their molecules and the deletion of Tyr151 and substitution of Pro152 for Gly in their autolysis loops when aligned with the sequences of tropical-zone fish and bovine trypsins. In addition, the contents of charged amino acid residues at the N-terminal regions (positions 20-50) of WP-T and AC-T were extremely higher than those of other fish and bovine trypsins. Moreover, one amino acid (Asn72) and two amino acids (Asn72 and Val75) coordinating with Ca<sup>2+</sup> in bovine trypsin were exchanged for another amino acids in WP-T (His) and AC-T (His and Glu), respectively, and the contents of negative charged amino acids at their Ca<sup>2+</sup>-binding regions were lower than those of tropical-zone fish and bovine trypsins. Therefore, it was considered that these structural characteristics of WP-T and AC-T are closely related to their lower thermostability. © 2011 Springer-Verlag.
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