China
Africa
Explore chapters and articles related to this topic
Brief Overview of Aspiring Properties of Functional Biopolymers for Food Packaging Applications
Published in Mohd Yusuf, Shafat Ahmad Khan, Biomaterials in Food Packaging, 2022
Pooja Agarwal, Anjali Gupta, Divya Tripathy
Application of PLA has increased in recent years because of its economical property and commercial feasibility. It is a biopolyester of 2-hydroxypropanoic acid commonly known as lactic acid. Microbial fermentation of carbohydrate is major source of lactic acid, and it also synthesizes chemically from petrochemicals. The lactic acid can exists in two stereo-isomeric forms: L(+) and D(-) lactic acids. Suitable microbe is used for the synthesis of required isomer L-lactic acid or D-lactic acid. There are three common methods to synthesize PLA viz: direct condensation of D- or L-lactic acid, dehydration polymerization method, and the most prominent method is ring opening polymerization of lactide dimer. The PLA obtained can be classified as poly(D-lactide) (PDLA), poly(L-lactide) (PLLA), and poly(D, L-lactide) (PDLLA), according to the isomer of lactide dimer selected, and all these isomeric forms of polymer have different properties [22–24].
Polylactic Acid: An Eco-Friendly Material in the Packaging Industry, Paving the Way Toward a Greener Environment
Published in Neha Kanwar Rawat, Iuliana Stoica, A. K. Haghi, Green Polymer Chemistry and Composites, 2021
S. Roopa, B. Sowmya, S. Preethi, Arul Maximus Rabel
PLA is thermoplastic aliphatic polyester which comprises of lactic acid repeating units. Lactic acid, a natural hydroxycarboxylic acid has been used in pharmaceutical, food industries, leather tanning, personal care, and in the production of polymers. About 39% of lactic acid is consumed for the production of biodegradable/biocompatible PLA polymer (Komesu et al., 2017). The chemical structure of lactic acid is given below (Fig. 4.1):
Citric Acid, Lactic Acid, and Acetic Acid Production
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
Lactic acid is an organic compound with the formula, CH3CH(OH)COOH. It is used as a food preservative, curing agent, and flavouring agent. Poly-lactic acid has tremendous potentiality in the medical applications. It is an ingredient in processed foods like cheese, yoghurt, kefir etc. and is also used as a decontaminant during meat processing. Lactic acid is produced commercially by fermentation of carbohydrates such as glucose, sucrose, or lactose, or by chemical synthesis.
Double-sided tuning effects of lactic acid on the hydration, microstructure and strength of supersulfated cement
Published in Journal of Sustainable Cement-Based Materials, 2023
Yang Zhou, Zechuan Peng, Luchuan Chen, Disheng Xu, Hao Wang
Hemihydrate gypsum was previously reported to result in better strength than anhydrite-activated SSC, which contributed to its high solubility [16, 17]. However, hemihydrate gypsum has not been widely adopted in SSC because of its consequent fast setting time. A traditional approach used to solve this problem has been to add retarders. However, one negative effect of a retarder is the decrease in strength [18]. In addition, short-chain organic acids (acetic, citric, tartaric, oxalic, succinic, etc.) have been used to modify the setting time of fresh cement paste [19]. In another study, citric acid was used as a retarder in an ettringite-based binder from ladle slag and gypsum [20]. Citric acid works as an inhibitor of ettringite formation, leading to the precipitation of monosulfate and gypsum, which can be ascribed to its strong chelating effect [19, 21]. Moreover, Masoudi [12] studied the effect of lactates on the hydration of SSC and confirmed that the lactate anion served as a chelating agent, which is beneficial to the hydration of slag. Our previous work came to a similar conclusion [22]. Lactic acid is a short-chain organic acid that can form lactate ions in solution. Therefore, lactic acid is a potential solution to act as a retarder and has no adverse effect on SSC strength.
Lactic acid wastewater treatment by photosynthetic bacteria and simultaneous production of protein and pigments
Published in Environmental Technology, 2022
Fan Meng, Meng Peng, Xintian Wang, Guangming Zhang
Lactic acid, an important raw material, is widely applied in the food, textile printing, chemical, pharmaceutical, leather, textile, etc. The industrial production of lactic acid generates great amount of wastewater. The lactic acid wastewater is characterized by high COD (2000–6000 mg/L), (60–180 mg/L) and very good biodegradability (BOD/COD > 0.6). The pollutants are mostly carbohydrates and their degradation products, which are non-toxic. The conventional treatment of this wastewater is anaerobic–aerobic activated sludge treatment that can easily reduce COD and but also generates high amount of excess sludge [16]. With rapidly increasing environment protection requirement, the treatment and disposal of excess sludge has been a big problem now. PSB were reported to effectively treat this kind of high nutritional and not-toxic wastewaters and produce valuable biomass [4,17]. It is naturally to assume that PSB are suitable for lactic acid wastewater treatment and value-added substances anabolism.
Synchronized extraction and purification of L-lactic acid from fermentation broth by emulsion liquid membrane technique
Published in Journal of Dispersion Science and Technology, 2018
Farhad Garavand, Seyed Hadi Razavi, Ilaria Cacciotti
Lactic acid is a colorless, water-soluble organic acid produced either by chemical synthesis or by microbial fermentation process. It is regarded as generally recognized as safe (GRAS) and can be used as an important natural organic acid in medicine, cosmetics, pharmaceuticals, detergents, and food industry, and as a precursor of polymers.[1] L-lactic acid, D-lactic acid, and racemic DL-lactic acid are lactic acid isomers, for which the pure forms (D- and L-lactic acid) are more appreciated due to their particular industrial applications. For example, poly L-lactic acid (PLLA), a valuable semi-crystalline thermostable biopolymer, is synthesized by the polymerization of L-lactic acid and is suitable for medical, cardiovascular, dental, and intestinal applications and sutures. Comparably, poly D-lactic acid (PDLA) is generated by the condensation of D-lactic acid and has more crystallinity, which results in low biodegradability in comparison with PLLA. Thus, the properties and the biodegradability of PLA biopolymers are determined by the ratio of L- and D-lactic acids.[2]