Biosynthesis of propionic acid using whey and calcium carbonate by mixed culture of Propionibacterium freundenreichii ATCC 6207 and Lactobacillus paracasei

Microparticles of Pereskia aculeata miller mucilage and sodium alginate for the encapsulation of Lactobacillus acidophilus ATCC 4356

Pereskia aculeata Miller (OPN) is a cactus species whose mucilage (MOPN) is rich in arabinogalactan, giving it great technological potential for the encapsulation of different compounds. This study aimed to synthesize microparticles of MOPN and sodium alginate (ALG) for the encapsulation of Lactobacillus acidophilus. The microparticles, produced by ionic gelation, were then coated with whey protein concentrate (WPC), or chitosan (CHI), or left uncoated (UC). Samples were characterized based on morphology, size, chemical structure, thermal properties, and performance under simulated digestion. The microparticles were porous and spherical, with average diameters ranging from 172.50 to 272.25 μm and encapsulation efficiency ranging from 74.73 % to 99.56 %. UCp microparticles produced with 0.6 % (w/w) MOPN and 0.9 % (w/w) ALG protected the probiotics against the extreme pH levels and digestive enzymes in the gastrointestinal tract, achieving a survival rate of 68.65 %. Coating with WPC (5.25 % w/w) did not improve microbial protection. The survival rate of the probiotic with WPC was 67.45 % and statistically equal to the value found for UCp microparticles Coating with CHI (1.2 % w/w) significantly reduced the survival rate to 63.27 %, likely due to increased porosity, lower microparticle stability, and the antimicrobial activity of chitosan. In comparison, the survival rate of free (unencapsulated) microorganisms was 56.58 %. These results indicate that the microparticles provided greater protection to L. acidophilus, suggesting that MOPN, in combination with other biopolymers, is an effective material for microbial encapsulation.

Critical factors influence on acidogenesis towards volatile fatty acid, biohydrogen and methane production from the molasses-spent wash

The study explored the spent wash valorisation into value added biobased products viz. volatile fatty acids (VFAs), biohydrogen (bio-H₂), methane (CH₄) and biohythane (bio-H-CNG) based on eight selected parameters employing design of experiment (DOE) approach. Selectively enriched biocatalyst showed marked influence on the production of acidogenic products (bio-H₂ and VFA) while untreated inoculum resulted in higher CH₄ and bio-H-CNG generation. CaCO₃ showed potential for butyric acid (H_Bu) production while Na₂CO₃ specifically yielded higher acetic acid (H_Ac) when supplemented as buffering agents. Higher degree of acidification (DOA; 49.8%) was observed at lower organic load (OL; 30 g/L). Biogas production and profile was influenced by OL, enrichment of biocatalyst and supplemented buffering agent. Higher OL related to higher bioproduct production, while yields of the respective products were higher at lower OL.

Microbial cell factories for the production of three-carbon backbone organic acids from agro-industrial wastes

At present, mass production of basic and valuable commodities is dependent on linear petroleum-based industries, which ultimately makes the depletion of finite natural reserves and accumulation of non-biodegradable and hazardous wastes. Therefore, an ecofriendly and sustainable solution should be established for a circular economy where infinite resources, such as agro-industrial wastes, are fully utilized as substrates in the production of target value-added chemicals. Hereby, recent advances in metabolic engineering strategies and techniques used in the development of microbial cell factories for enhanced production of three-carbon platform chemicals such as lactic acid, propionic acid, and 3-hydroxypropionic acid are discussed. Further developments and future perspectives in the production of these organic acids from agro-industrial wastes from the dairy, sugar, and biodiesel industries are also highlighted to demonstrate the importance of waste-based biorefineries for organic acid production.