Browsing by Author "Sukhumaporn Krajangsang"

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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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    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.
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    Production of poly (l-lactide)-degrading enzyme by Actinomadura keratinilytica strain T16-1 under solid state fermentation using agricultural wastes as substrate
    (Springer Science and Business Media Deutschland GmbH, 2021) Sukhumaporn Krajangsang; Nuttanisa Dechsresawut; Thanasak Lomthong; Srisuda Samaimai; S. Samaimai; Faculty of Science and Technology, Suan Dusit University, Bangkok, 10700, Thailand; email: srisuda_sam@dusit.ac.th
    Poly (l-lactide) (PLLA) is an aliphatic polyester that can be obtained from renewable resources and degraded by various microorganisms. In previous reports, Actinomadura keratinilytica strain T16-1 demonstrated high ability to degrade PLLA under various conditions. PLLA-degrading enzyme production under solid state fermentation has been sparsely studied. PLLA-degrading enzyme production by A. keratinilytica strain T16-1 was investigated using agricultural wastes as substrate under solid state fermentation (SSF). Three agricultural wastes as soybean meal, cassava chips and duckweed were tested as substrates for PLLA-degrading enzyme production by statistical methods using mixture design. Results revealed that using duckweed as the substrate gave the highest enzyme production (138.66 ± 13.57 U/g dry substrate). Maximum enzyme activity of 391.24 ± 15.57 U/g dry substrate was obtained under 10Êg duckweed, 10% inoculum size, 7Êdays of cultivation time, pH 7.0, 2.8% PLLA powder, and 60% moisture content at 45Ê¡C. It can be concluded that duckweed is an inexpensive substrate, which reduces the costs of PLLA-degrading enzyme production, as an alternative to effective water weed management. © 2021, King Abdulaziz City for Science and Technology.