Browsing by Author "Vichien Kitpreechavanich"

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    Co-production of poly(l-lactide)-degrading enzyme and raw starch-degrading enzyme by Laceyella sacchari LP175 using agricultural products as substrate, and their efficiency on biodegradation of poly(l-lactide)/thermoplastic starch blend film
    (Elsevier Ltd, 2015) Thanasak Lomthong; Srisuda Hanphakphoom; Rangrong Yoksan; Vichien Kitpreechavanich
    The co-production of poly-(l-lactide)-degrading enzyme and raw starch-degrading enzyme by the thermophilic filamentous bacterium Laceyella sacchari LP175 in liquid medium using low-cost agricultural crops as substrates was investigated. Statistical mixture design experiments indicated that 5g of raw material - consisting of 2.35gL-1 cassava chips and 2.65gL-1 soybean meal in a suspension of 2.0gL-1 K2HPO4 and 1.0gL-1 KH2PO4 - gave the highest production of both enzymes when the culture was grown at 50�C for 24h cultivation. Addition of 1.0gL-1 of poly-(l-lactide) powder and 1.0gL-1 cassava starch to the medium increased poly-(l-lactide)-degrading enzyme and raw starch-degrading enzyme, respectively. Response surface methodology by central composite design found that the optimized concentration of 0.52gL-1 poly(l-lactide) powder and 3.34gL-1 cassava starch increased poly-(l-lactide)-degrading enzyme and raw starch-degrading enzyme activities up to 68.8UmL-1 and 86.1UmL-1, respectively. The 2% poly-(l-lactide)/thermoplastic starch (PLLA/TPS) blend (50:50) film was degraded up to 99.7% of weight loss by the crude enzyme at an initial pH of 9.0 for 4h. The high efficiency on biodegradation of poly-(l-lactide)/thermoplastic starch blend polymer by the obtained mixed enzymes from cheap and abundant agricultural products could be applied to reduce global environment from non-biodegradable materials. � 2015 Elsevier Ltd.
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    Degradation of poly(Butylene succinate) and poly(butylene succinate)/poly(lactide) blends using serine protease produced from laceyella sacchari LP175
    (Walailak University, 2021) Srisuda Samaimai; Sukhumaporn Krajangsang; Vichien Kitpreechavanich; Jednipit Borthong; Thanasak Lomthong; T. Lomthong; Division of Biology, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi, Pathum Thani, 12110, Thailand; email: thanasak_l@rmutt.ac.th
    The thermophilic filamentous bacterium Laceyella sacchari LP175 was cultivated in a 10.0 L airlift fermenter to produce serine protease at 50 ¡C. Maximal serine protease activity at 1,123.32 ± 15.8 U/mL was obtained for cultivation at 0.6 vvm aeration rate for 36 h. The crude enzyme was applied for degradation of poly (butylene succinate) (PBS), and poly (butylene succinate)/poly(lactide) blend (PBS/PLA) powders at 50 ¡C for 48 h with different substrates and enzyme concentrations. Results showed that serine protease produced from L. sacchari LP175 degraded PBS and PBS/PLA at 46.5 ± 2.05 and 49.8 ± 1.45 %, respectively, at an initial substrate concentration of 100 g/L with 1,200 U/mL of serine protease activity. Percentage degradation of PBS and PBS/PLA was improved to 51.4 ± 1.06 and 56.9 ± 1.42 %, respectively, when upscaled in a 2.0 L stirrer fermenter with 200 rpm agitation rate. Degradation products evaluated by a scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) confirmed that serine protease produced from L. sacchari LP175 degraded both PBS and PBS/PLA polymers. Results showed that microbial enzyme technology could be used to degrade PBS and PBS/PLA blend polymers and reduce the accumulation of waste. © 2021, Walailak University. All rights reserved.
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    Enhancement of poly(L-lactide)-degrading enzyme production by Laceyella sacchari LP175 using agricultural crops as substrates and its degradation of poly(L-lactide) polymer
    (Elsevier Ltd, 2017) Thanasak Lomthong; Srisuda Hanphakphoom; Prachumporn Kongsaeree; Nantana Srisuk; Marie Guicherd; Gianluca Cioci; Sophie Duquesne; Alain Marty; Vichien Kitpreechavanich; V. Kitpreechavanich; Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand; email: fsciwck@ku.ac.th
    Optimization of the medium for poly(L-lactide) (PLLA)-degrading enzyme production in shake flask experiments was investigated using agricultural products as substrates. Cassava chips and soybean meal were the best carbon and nitrogen sources, respectively, as determined by the one-factor-at-a-time method. Enzyme production was significantly enhanced by the addition of phosphates, but was suppressed by the addition of ammonium salt. The maximum enzyme production, 65.5 U/mL, was obtained from the optimized medium consisting of 4.64 g/L cassava chips, 1.53 g/L soybean meal and 0.31 g/L PLLA powder using central composite design in the basal medium. The optimal physical factors in 3 L airlift fermenter were 50 �C, pH 7.0 and 0.5 vvm aeration rate for 18 h, yielded 94.4 U/mL. The crude enzyme was shown to be able to hydrolyze PLLA powder (91%) at 50 �C in 72 h which showed high efficiency for recycling of PLLA polymer and reducing the global environmental problem. � 2017 Elsevier Ltd
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    High Loading Degradation of Poly(lactide)/Thermoplastic Starch Blend Film Using Mixed-Enzymes Produced by Fed-Batch Culture of Laceyella sacchari LP175
    (Springer Science and Business Media B.V., 2022) Thanasak Lomthong; Srisuda Samaimai; Rangrong Yoksan; Sukhumaporn Krajangsang; Vichien Kitpreechavanich; V. Kitpreechavanich; Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand; email: fsciwck@ku.ac.th
    Purpose: Co-production of poly(l-lactide) (PLLA)-degrading enzyme and raw starch-degrading enzyme (RSDE) was investigated using a fed-batch culture of Laceyella sacchari LP175 in a 10.0ÊL airlift fermenter. Agricultural products were used as substrates for production of enzymes to degrade the poly(lactide)/thermoplastic starch blend film at high concentration. Methods: Fed-batch culture was performed in a 10.0ÊL airlift fermenter for co-production of PLLA-degrading enzyme and RSDE by L. sacchari LP175. Parameters affecting PLA/thermoplastic starch (TPS) blend film at high loading (100Êg/L) degradation were optimized using response surface methodology (RSM) with a central composite design (CCD) at 50Ê¡C for 24Êh. Results: Maximum enzyme production of PLLA-degrading enzyme and RSDE at 91.6 ± 7.21 and 120.1 ± 9.33 U/mL, respectively, were obtained when incubated at 50Ê¡C for 42Êh after adding raw cassava starch (3.34Êg/L) and PLA powder (0.52Êg/L) at 30Êh of cultivation. The optimum conditions for degradation (92.23%) from the model were enzyme concentration at 0.6% (w/v), time to add CaCO3 3Êh after digestion and 0.2ÊM of Tris-HCl buffer (pH 9.0) in the shaking flask scale with a 95% significance level (p < 0.05). These conditions gave the highest degradation at 90.65 ± 4.03% from the actual experimental. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) revealed the mixed enzymes produced by L. sacchari LP175 hydrolyzed PLA/TPS blend film at 50Ê¡C. Conclusions: Results indicated the feasibility of producing mixed enzymes by L. sacchari LP175 and hydrolysis of PLA/TPS blend film at high concentration to reduce waste accumulation through biotechnological processes. Graphical Abstract: [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to Springer Nature B.V.