Optimized production of poly (γ-glutamic acid) (γ-PGA) using Bacillus licheniformis and its application as cryoprotectant for probiotics.

Bacteria produce poly (γ-glutamic acid) (γ-PGA), a polymer of l- or d-glutamic acid, as a defense response and have gained importance due to their applications in food and pharmaceutical industry. In the present investigation, production of γ-PGA using cost-effective carbon substrate, characterization of the produced polymer, and its application as cryoprotectant for selected freeze-dried probiotic bacteria were investigated. Central composite rotatable design of response surface methodology was used to study the main and the interactive effects of medium components: rice bran and casein peptone concentration.

Optimization of Levan Production by Cold-Active Bacillus licheniformis ANT 179 and Fructooligosaccharide Synthesis by Its Levansucrase.

Fructooligosaccharides (FOS) and levan attract much attention due to a wide range of applications in food technology and pharmaceutical and cosmetic industry. Bacillus licheniformis ANT 179, isolated from Antarctica soil, produced levansucrase and levan in a medium containing sucrose as carbon substrate. In this study, characterization of levansucrase and production of short-chain FOS and levan were investigated.

Material Properties and Antimicrobial Activity of Polyhydroxybutyrate (PHB) Films Incorporated with Vanillin.

Polyhydroxybutyrate (PHB) was produced by Bacillus mycoides DFC 1, isolated from garden soil. Antimicrobial (AM) films of PHB were prepared by incorporating vanillin (4-hydroxy-3-methoxybenzaldehyde) from 10 to 200 μg/g of PHB. The films were assessed for antimicrobial activity against foodborne pathogens and spoilage bacteria comprising of Escherichia coli, Salmonella typhimurium, Shigella flexneri, and Staphylococcus aureus and fungi such as Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus parasiticus, Aspergillus ochraceus, Penicillium viridicatum, and Penicillium clavigerum.

Occurrence of Cellulose-Producing Gluconacetobacter spp. in Fruit Samples and Kombucha Tea, and Production of the Biopolymer.

Cellulose producing bacteria were isolated from fruit samples and kombucha tea (a fermented beverage) using CuSO4 solution in modified Watanabe and Yamanaka medium to inhibit yeasts and molds. Six bacterial strains showing cellulose production were isolated and identified by 16S rRNA gene sequencing as Gluconacetobacter xylinus strain DFBT, Ga. xylinus strain dfr-1, Gluconobacter oxydans strain dfr-2, G.

Hybrid HPMC nanocomposites containing bacterial cellulose nanocrystals and silver nanoparticles.

Hydroxypropyl methyl cellulose (HPMC) based hybrid nanocomposites reinforced with bacterial cellulose nanocrystals (BCNC) and silver nanoparticles (AgNPs) had been prepared and characterised. BCNC was capable of improving the tensile strength and modulus of HPMC, but they made the film more brittle. The addition of AgNPs along with BCNC, helped to regain some of the lost elongation properties without affecting other properties.

Synergized antimicrobial activity of eugenol incorporated polyhydroxybutyrate films against food spoilage microorganisms in conjunction with pediocin.

Biopolymers and biopreservatives produced by microorganisms play an essential role in food technology. Polyhydroxyalkanoates and bacteriocins produced by bacteria are promising components to safeguard the environment and for food preservation applications. Polyhydroxybutyrate (PHB)-based antimicrobial films were prepared incorporating eugenol, from 10 to 200 μg/g of PHB.

Characterization of chemically treated bacterial (Acetobacter xylinum) biopolymer: some thermo-mechanical properties.

Bacterial cellulose prepared from pellicles of Acetobacter xylinum (Gluconacetobacter xylinus) is a unique biopolymer in terms of its molecular structure, mechanical strength and chemical stability. The biochemical analysis revealed that various alkali treatment methods were effective in removing proteins and nucleic acids from native membrane resulting in pure cellulose membrane. The effect of various treatment regimens on thermo-mechanical properties of the material was investigated.