ABSTRACT
A halophilic mangrove isolate identified by 16S rRNA sequence as a Bacillus spp. was found to be capable of using a broad range of carbon sources including monosaccharides (glucose and fructose), disaccharides (sucrose), pentoses (xylose and arabinose), various organic acids (acetic acid, propionic acid and octanoic acid) and even the acid pre-treated liquor (APL) of sugarcane trash, a lignocellulosic biomass, for growth and the production of polyhydroxyalkanoates (PHAs) such as poly(3-hydroxybutyrate, P3HB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate, PHBV), and 4-hydroxyhexanoate, 4HHX). The study describes the innate ability of a wild-type culture for PHBV production by both propionate dependent and propionate independent pathways. The biopolymer was extracted and characterized physico-chemically. The PHBV yield from glucose was estimated to be 73% of biomass weight with a high 3-hydroxyvalerate fraction of 48mol%. Thereafter, spherical homogenous PHBV nanoparticles of â¼164nm size were prepared for future applications.
Subject(s)
Bacillus/isolation & purification , Halogens/pharmacology , Pentanoic Acids/metabolism , Polyesters/metabolism , Wetlands , Bacillus/drug effects , Bacillus/metabolism , Biomass , Calorimetry, Differential Scanning , Carbon/pharmacology , Nanoparticles/chemistry , Phylogeny , Propionates/metabolism , Proton Magnetic Resonance Spectroscopy , RNA, Ribosomal, 16S/genetics , Saccharum/chemistry , Spectroscopy, Fourier Transform Infrared , Waste ProductsABSTRACT
To characterize the physicochemical and biological stability of nanodevices suitable for biomedical applications, polylactic acid (PLA) nanoparticles (NPs) of 112 ± 6 nm and polyhydroxy butyrate (PHB) of 15 ± 5 nm size were prepared by standardizing the suitable method for each. Morphology of NPs was studied by scanning and transmission electron microscopy and temperature stability by thermogravimetric analysis. Their stability in biological fluids (simulated gastrointestinal and saliva) and tolerance against 0.5 mM NaCl were analyzed. PHB NPs remained stable in all fluids, while after 24 h treatment, the PLA NPs showed the beginning of disintegration with intestinal fluid mimic. In addition to the preparation of polyethylene glycol (PEG) surface-coated NPs, PLA-PEG-PLA triblock copolymer (MW â¼ 7,366 Da) was also chemically synthesized and characterized. Cytotoxicity of all forms of nanoparticles was tested by MTT assay and by annexin pi staining.
