Potential use of Bacillus paramycoides for the production of the biopolymer polyhydroxybutyrate from leftover carob fruit agro-waste

Evaluation of the Method of Periodic Medium Renewal of Bacillus aryabhattai RAF 5 and Analysis of P(3HB) Production

The purpose of this study was to assess the ability of Bacillus aryabhattai RAF 5 to produce P(3HB) under conditions of periodic medium renewal (PMR). The producer was isolated and confirmed using transmission electron microscopy (TEM), which revealed the presence of more than 10 dense P(3HB) granules per cell. The purity of the isolated polymer was evaluated using Fourier transform infrared spectroscopy (FTIR). The maximum concentration of P(3HB) reached 18.70 g/L with biomass accumulation of 21.44 g/L after 120 h of incubation under PMR conditions, which is 6.61 g/L higher than the concentration of P(3HB) obtained with the standard cultivation method. The resulting polymer was later used to create a membrane, which was then tested for permeability to water vapor, oxygen, carbon dioxide, and a biofilm puncture test. The resulting P(3HB)-based membranes have promising barrier properties, indicating their suitability for various industrial applications, including biomedical devices.

Purification and biochemical characterization of pullulanase produced from Bacillus sp. modified by ethyl-methyl sulfonate for improved applications

Strain improvement via chemical mutagen could impart traits with better enzyme production or improved characteristics. The present study sought to investigate the physicochemical properties of pullulanase produced from the wild Bacillus sp and the mutant. The pullulanases produced from the wild and the mutant Bacillus sp. (obtained via induction with ethyl methyl sulfonate) were purified in a-three step purification procedure and were also characterized. The wild and mutant pullulanases, which have molecular masses of 40 and 43.23 kDa, showed yields of 2.3% with 6.0-fold purification and 2.0% with 5.0-fold purification, respectively, and were most active at 50 and 40 °C and pH 7 and 8, respectively. The highest stability of the wild and mutant was between 40 and 50 °C after 1 h, although the mutant retained greater enzymatic activity between pH 6 and 9 than the wild. The mutant had a decreased Km of 0.03 mM as opposed to the wild type of 1.6 mM. In comparison to the wild, the mutant demonstrated a better capacity for tolerating metal ions and chelating agents. These exceptional characteristics of the mutant pullulanase may have been caused by a single mutation, which could improve its utility in industrial and commercial applications.