The biodegradable polymer matrices used in this study were PHB biosynthesized from fructose by Cupriavidus necator strain A-04 according to a previous report [13 (link), 23 (link)]. Batch cultivation was performed in a 10-L bioreactor (MDL-10L, B.E. Marubishi Co., Ltd., Tokyo, Japan). Culture samples were periodically harvested for analysis of the dry cell weight (DCW), PHB, carbon and nitrogen concentrations. The harvested cells were dried, placed in filter paper (Whatman 1002–042, Sigma–Aldrich Corp., St. Louis, MO, USA) and then refluxed in hot chloroform in a Soxhlet apparatus to extract PHBA-04 from the dried cells. The PHBA-04 was precipitated from a chloroform solution using three volumes of n-hexane. The precipitation step was repeated three times [24 , 25 (link)].
As a binder and filler, the agro-industrial residue used in this study was pineapple leaves (Ananas comosus L. Merr.) obtained from Siam Food Products Public Company Limited (Rai Nong Takhian at Tambol Khlong Kaeo, Amphoe Banbung, Chonburi, Thailand). The pineapple leaves were washed repeatedly with distilled water to remove all the dirt, immersed in 5% sodium hypochlorite solution for 1 h, cut into approximately 2 cm × 2 cm pieces, dried in a hot-air oven (UN55, Memmert Co., Ltd., Schwabach, Germany) at 65°C for 24 h, milled using a laboratory blender (45,000 rpm, 1800-W, Healthy mix GP 3.5, Taiwan) and then sieved to fractionate the particle sizes between 0.420 and 0.250 mm (− 40/+ 60 mesh). The chemical composition of the dried pineapple leaves was determined according to the Technical Association of Pulp and Paper Industry (TAPPI) standard methods for the following parameters: benzene extractives (TAPPI T204 cm-07); α-cellulose, β-cellulose, and γ-cellulose (TAPPI T203 om-09); holocellulose (TAPPI T9 m-54; lignin (TAPPI T222 om-15); and ash (TAPPI T-211). Dried pineapple leaves with a particle size of approximately 2 cm × 2 cm were used to extract PALF-MCC.
N,N-Dimethylacetamide (DMAc, RCI Labscan Ltd., Thailand) and anhydrous lithium chloride (LiCl, ≥ 98%, Elago Enterprises Pty Ltd., N.S.W., Australia) were used as solvents, while N,N-dimethyl 1-4-aminopyridine (DMAP, 98%, Fluka) was applied as the catalyst. The esterifying agent was lauroyl chloride (TCI Co., Ltd., Tokyo, Japan). Hydrochloric acid (Merck KGaA, Darmstadt, Germany) was used for hydrolysis, and ethanol (Merck KGaA, Darmstadt, Germany) was used as the precipitating agent.
As a binder and filler, the agro-industrial residue used in this study was pineapple leaves (Ananas comosus L. Merr.) obtained from Siam Food Products Public Company Limited (Rai Nong Takhian at Tambol Khlong Kaeo, Amphoe Banbung, Chonburi, Thailand). The pineapple leaves were washed repeatedly with distilled water to remove all the dirt, immersed in 5% sodium hypochlorite solution for 1 h, cut into approximately 2 cm × 2 cm pieces, dried in a hot-air oven (UN55, Memmert Co., Ltd., Schwabach, Germany) at 65°C for 24 h, milled using a laboratory blender (45,000 rpm, 1800-W, Healthy mix GP 3.5, Taiwan) and then sieved to fractionate the particle sizes between 0.420 and 0.250 mm (− 40/+ 60 mesh). The chemical composition of the dried pineapple leaves was determined according to the Technical Association of Pulp and Paper Industry (TAPPI) standard methods for the following parameters: benzene extractives (TAPPI T204 cm-07); α-cellulose, β-cellulose, and γ-cellulose (TAPPI T203 om-09); holocellulose (TAPPI T9 m-54; lignin (TAPPI T222 om-15); and ash (TAPPI T-211). Dried pineapple leaves with a particle size of approximately 2 cm × 2 cm were used to extract PALF-MCC.
N,N-Dimethylacetamide (DMAc, RCI Labscan Ltd., Thailand) and anhydrous lithium chloride (LiCl, ≥ 98%, Elago Enterprises Pty Ltd., N.S.W., Australia) were used as solvents, while N,N-dimethyl 1-4-aminopyridine (DMAP, 98%, Fluka) was applied as the catalyst. The esterifying agent was lauroyl chloride (TCI Co., Ltd., Tokyo, Japan). Hydrochloric acid (Merck KGaA, Darmstadt, Germany) was used for hydrolysis, and ethanol (Merck KGaA, Darmstadt, Germany) was used as the precipitating agent.
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