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Optimization of bio-succinic fermentation process from crude glycerol by Actinobacillus succinogenes
Suwimon Kanchanasuta,Verawat Champreda,Nipon Pisutpaisal,Chatchawal Singhakant 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.4
Bio-succinic acid is a commodity chemical with potent application in bioplastic and food industries which can be produced from renewable resources. In this study, bioprocess for production of bio-succinic from glycerol by Actinobacillus succinogenes was studied. The maximum succinic acid concentration in small-scale serum bottle experiments was 6.8 and 6.5 g/L using pure and crude glycerol, respectively, with supplemented MgCO₃. The ratio of acetic acid to succinic acid (AA/SA) implied the increased carbon flux to the C₄ pathway using crude glycerol supplemented with MgCO₃ compared to that with CaCO₃.The carbonate salts tended to induce C₃ metabolic pathway in fermentation using pure glycerol which was in accordance with the ratio of acetic acid to glycerol (AA/GL). The highest succinic acid concentration of 17.9 g/L from crude glycerol was achieved from batch fermentation in a lab-scale fermenter with the maximum glycerol utilization of 99.9% which were higher than those obtained from fed- batch and semi-continuous processes. Acetic acid tended to increase throughout the fermentation process in fed-batch and semi-continuous operations, which resulted in the lower product yield and substrate utilization efficiency. The time for initial purging of CO₂ showed effects on succinic acid production and internal metabolic pathways. This work provided a basis for process development on bio-succinic acid production from crude glycerol in industry.
Trakarnpaiboon Srisakul,Champreda Verawat 한국미생물·생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.8
Trehalose is a non-conventional sugar with potent applications in the food, healthcare and biopharma industries. In this study, trehalose was synthesized from maltose using whole-cell Pseudomonas monteilii TBRC 1196 producing trehalose synthase (TreS) as the biocatalyst. The reaction condition was optimized using 1% Triton X-100 permeabilized cells. According to our central composite design (CCD) experiment, the optimal process was achieved at 35oC and pH 8.0 for 24 h, resulting in the maximum trehalose yield of 51.60 g/g after 12 h using an initial cell loading of 94 g/l. Scale-up production in a lab-scale bioreactor led to the final trehalose concentration of 51.91 g/l with a yield of 51.60 g/g and productivity of 4.37 g/l/h together with 8.24 g/l glucose as a byproduct. A one-pot process integrating trehalose production and byproduct bioremoval showed 53.35% trehalose yield from 107.4 g/l after 15 h by permeabilized P. moteilii cells. The residual maltose and glucose were subsequently removed by Saccharomyces cerevisiae TBRC 12153, resulting in trehalose recovery of 99.23% with 24.85 g/l ethanol obtained as a co-product. The present work provides an integrated alternative process for trehalose production from maltose syrup in bio-industry.
( Surisa Suwannarangsee ),( Jantima Arnthong ),( Lily Eurwilaichitr ),( Verawat Champreda ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.10
Enzymatic hydrolysis of lignocellulosic biomass into fermentable sugars is a key step in the conversion of agricultural by-products to biofuels and value-added chemicals. Utilization of a robust microorganism for on-site production of biomass-degrading enzymes has gained increasing interest as an economical approach for supplying enzymes to biorefinery processes. In this study, production of multi-polysaccharide-degrading enzymes from Aspergillus aculeatus BCC199 by solid-state fermentation was improved through the statistical design approach. Among the operational parameters, yeast extract and soybean meal as well as the nonionic surfactant Tween 20 and initial pH were found as key parameters for maximizing production of cellulolytic and hemicellulolytic enzymes. Under the optimized condition, the production of FPase, endoglucanase, β-glucosidase, xylanase, and β-xylosidase was achieved at 23, 663, 88, 1,633, and 90 units/g of dry substrate, respectively. The multi-enzyme extract was highly efficient in the saccharification of alkaline-pretreated rice straw, corn cob, and corn stover. In comparison with commercial cellulase preparations, the BCC199 enzyme mixture was able to produce remarkable yields of glucose and xylose, as it contained higher relative activities of β-glucosidase and core hemicellulases (xylanase and β-xylosidase). These results suggested that the crude enzyme extract from A. aculeatus BCC199 possesses balanced cellulolytic and xylanolytic activities required for the efficient saccharification of lignocellulosic biomass feedstocks, and supplementation of external β-glucosidase or xylanase was dispensable. The work thus demonstrates the high potential of A. aculeatus BCC199 as a promising producer of lignocellulose-degrading enzymes for the biomass conversion industry.
( Srisakul Trakarnpaiboon ),( Benjarat Bunterngsook ),( Rungtiva Wansuksriand ),( Verawat Champreda ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.10
Trehalose is a non-reducing disaccharide in increasing demand for applications in food, nutraceutical, and pharmaceutical industries. Single-step trehalose production by trehalose synthase (TreS) using maltose as a starting material is a promising alternative process for industrial application due to its simplicity and cost advantage. Pseudomonas monteilii TBRC 1196 was identified using the developed screening method as a potent strain for TreS production. The TreS gene from P. monteilii TBRC 1196 was first cloned and expressed in Escherichia coli. Purified recombinant trehalose synthase (PmTreS) had a molecular weight of 76 kDa and showed optimal pH and temperature at 9.0 and 40°C, respectively. The enzyme exhibited >90% residual activity under mesophilic condition under a broad pH range of 7-10 for 6 h. Maximum trehalose yield by PmTreS was 68.1% with low yield of glucose (4%) as a byproduct under optimal conditions, equivalent to productivity of 4.5 g/l/h using enzyme loading of 2 mg/g substrate and high concentration maltose solution (100 g/l) in a lab-scale bioreactor. The enzyme represents a potent biocatalyst for energysaving trehalose production with potential for inhibiting microbial contamination by alkaline condition.
Thermostable Xylanase from Marasmius sp.: Purification and Characterization
Ratanachomsri, Ukrit,Sriprang, Rutchadaporn,Sornlek, Warasirin,Buaban, Benchaporn,Champreda, Verawat,Tanapongpipat, Sutipa,Eurwilaichitr, Lily Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.1
We have screened 766 strains of fungi from the BIOTEC Culture Collection (BCC) for xylanases working in extreme pH and/or high temperature conditions, the so-called extreme xylanases. From a total number of 32 strains producing extreme xylanases, the strain BCC7928, identified by using the internal transcribed spacer (ITS) sequence of rRNA to be a Marasmius sp., was chosen for further characterization because of its high xylanolytic activity at temperature as high as $90^{\circ}C$. The crude enzyme possessed high thermostability and pH stability. Purification of this xylanase was carried out using an anion exchanger followed by hydrophobic interaction chromatography, yielding the enzyme with >90% homogeneity. The molecular mass of the enzyme was approximately 40 kDa. The purified enzyme retained broad working pH range of 4-8 and optimal temperature of $90^{\circ}C$. When using xylan from birchwood as substrate, it exhibits $K_m$ and $V_{max}$ values of $2.6{\pm}0.6\;mg/ml$ and $428{\pm}26\;U/mg$, respectively. The enzyme rapidly hydrolysed xylans from birchwood, beechwood, and exhibited lower activity on xylan from wheatbran, or celluloses from carboxymethylcellulose and Avicel. The purified enzyme was highly stable at temperature ranges from 50 to $70^{\circ}C$. It retained 84% of its maximal activity after incubation in standard buffer containing 1% xylan substrate at $70^{\circ}C$ for 3 h. This thermostable xylanase should therefore be useful for several industrial applications, such as agricultural, food and biofuel.