Polyhydroxyalkanoate Recovery From Newly Screened Bacillus Sp. LPPI-81 Using Various Methods of Extraction From Loktak Lake Sediment Sample

Abstract

Nowadays the conventional plastic wastes are very challenging to environments and its production cost also creates an economic crisis due to petrochemical-based plastic. In order to solve this problem, the current studies were aimed at screening and characterizing these PHA producing isolates and evaluating the suitability of some carbon source for newly screened PHA producing isolates. Some carbon sources such as D-fructose, glucose, molasses, D-ribose and sucrose were evaluated for PHA production. Data were analyzed using SPSS version 20. The 16SrRNA gene sequence of these isolates was performed. This newly isolated taxa was related to Bacillus species. It was designed as Bacillus sp. LPPI-18 and affiliated Bacillus cereus ATCC 14577T (AE01687) (99.10%). Paenibacillus sp. 172 (AF273740.1) was used as an out-group. Bacillus sp. LPPI-18 is a gram-positive, rod-shaped, endospore former, and citrate test positive. This isolate showed positive for amylase, catalase, pectinase, and protease test. They produced intracellular PHA granules when this isolate was stained with Sudan Black B (SBB) and Nile Blue A (NBA) preliminary and specific staining dyes, respectively. Both Temperature and pH used to affect PHA productivity. Bacteria are able to reserve PHA in the form of granules during stress conditions. This isolate produces only when supplied with carbon sources. More PHA contents (PCs) were obtained from glucose, molasses, and D-fructose. In this regard, the maximum mean value of PC was obtained from glucose (40.55±0.7%) and the minimum was obtained from D-Ribose (12.4±1.4%). Great variations (p≤0.05) of PCs were observed among glucose & sucrose, molasses & sucrose and D-fructose & sucrose carbon sources for PHA productivity (PP) of Cell Dry Weight (CDW) g/L. After extraction, PHA film was produced for this typical isolate using glucose as a sole carbon source. Fourier transform infrared spectrum was performed for this isolate and showed the feature of polyester at 1719.64 to 1721.16 wavelength for these extracted samples. The peak of fingerprinting (band of carboxylic acid group) at this wave-length is a characteristic feature of PHB and corresponds to the ester functional group (C=O).

Isolation, screening, and characterization of polyhydroxyalkanoate (PHA)‐producing Cellulosimicrobium cellulans: A promising approach for eco‐friendly biopolymer production

“…It was applied to distinguish PHA-producing isolates from PHA-negative bacteria. 33 Among the seven isolates screened from SSB staining, only three isolates SS2, SSNA 1a, and SF2 isolates showed strong reddish-orange fluorescence when exposed to UV light confirming the presence of PHA granules (Figure S3). More than 20 bacterial taxa, including Bacillus, Alcaligens, Pseudomonas, Rhizobium, Azotobacter, and Rhizospirillum, have been found to harbor the PHB.…”

“…PHA‐positive colonies will fluoresce when exposed to UV light. It was applied to distinguish PHA‐producing isolates from PHA‐negative bacteria 33 . Among the seven isolates screened from SSB staining, only three isolates SS2, SSNA 1a, and SF2 isolates showed strong reddish‐orange fluorescence when exposed to UV light confirming the presence of PHA granules (Figure S3).…”