L-Poly(lactic acid) Production by Microwave Irradiation of Lactic Acid Obtained from Lignocellulosic Wastes.

Content Provider	Europe PMC
Author	Senila, Lacrimioara Cadar, Oana Kovacs, Eniko Gal, Emese Dan, Monica Stupar, Zamfira Simedru, Dorina Senila, Marin Roman, Cecilia
Editor	Mayo, Baltasar
Copyright Year	2023
Abstract	L-polylactic acid (PLA), a semi-crystalline aliphatic polyester, is one of the most manufactured biodegradable plastics worldwide. The objective of the study was to obtain L-polylactic acid (PLA) from lignocellulosic plum biomass. Initially, the biomass was processed via pressurized hot water pretreatment at a temperature of 180 °C for 30 min at 10 MPa for carbohydrate separation. Cellulase and the beta-glucosidase enzymes were then added, and the mixture was fermented with Lacticaseibacillus rhamnosus ATCC 7469. The resulting lactic acid was concentrated and purified after ammonium sulphate and n-butanol extraction. The productivity of L-lactic acid was 2.04 ± 0.18 g/L/h. Then, the PLA was synthesized in two stages. Firstly, lactic acid was subjected to azeotropic dehydration at 140 °C for 24 h in the presence of xylene, using SnCl2 (0.4 wt.%) as a catalyst, resulting in lactide (CPLA). Secondly, microwave-assisted polymerization was carried out at 140 °C for 30 min with 0.4 wt.% SnCl2. The resulting powder was purified with methanol to produce PLA with 92.1% yield. The obtained PLA was confirmed using electrospray ionization mass spectrometry, nuclear magnetic resonance, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. Overall, the resulting PLA can successfully replace the traditional synthetic polymers used in the packaging industry.
Journal	International Journal of Molecular Sciences [Int J Mol Sci]
Volume Number	24
DOI	10.3390/ijms24129817
PubMed Central reference number	PMC10298539
Issue Number	12
PubMed reference number	37372965
e-ISSN	14220067
Language	English
Publisher	Molecular Diversity Preservation International (MDPI)
Publisher Date	2023-06-06
Access Restriction	Open
Subject Keyword	L-polylactic acid renewable biomass simultaneous saccharification and fermentation lactic acid
Content Type	Text
Resource Type	Article
Subject	Physical and Theoretical Chemistry Molecular Biology Spectroscopy Catalysis Computer Science Applications Medicine Inorganic Chemistry Organic Chemistry