microorganisms Article Bioplastic Production by Bacillus wiedmannii AS-02 OK576278 Using Different Agricultural Wastes Amal W. Danial 1 , Shereen M. Hamdy 2 , Sulaiman A. Alrumman 3 , Sanaa M. F. Gad El-Rab 1 , Ahmed A. M. Shoreit 1, * and Abd El-Latif Hesham 4, *   Citation: Danial, A.W.; Hamdy, S.M.; Alrumman, S.A.; Gad El-Rab, S.M.F.; Shoreit, A.A.M.; Hesham, A.E.-L. Bioplastic Production by Bacillus wiedmannii AS-02 OK576278 Using Different Agricultural Wastes. Microorganisms 2021, 9, 2395. https://doi.org/10.3390/ microorganisms9112395 Academic Editor: Giovanni Vallini Received: 25 September 2021 Accepted: 18 November 2021 Published: 21 November 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Botany and Microbiology Department, Faculty of Science, Assiut University, Assiut 71516, Egypt; daniala.w@aun.edu.eg (A.W.D.); sanaafahmy@aun.edu.eg (S.M.F.G.E.-R.) 2 Pediatric Hospital, Assiut University, Assiut 71516, Egypt; Shereenhamdy80@yahoo.com 3 Biology Department, College of Science, King Khalid University, Abha 61413, Saudi Arabia; salrumman@kku.edu.sa 4 Genetics Department, Faculty of Agriculture, Beni-Suef University, Beni Suef 62521, Egypt * Correspondence: ashoreit1968@yahoo.com (A.A.M.S.); hesham_egypt5@agr.bsu.edu.eg (A.E.-L.H.) Abstract: Polyhydroxybutyrates (PHBs) are macromolecules synthesized by bacteria. Because of their fast degradability under natural environmental conditions, PHBs were selected as alternatives for the production of biodegradable plastics. Sixteen PHB-accumulating strains were selected and compared for their ability to accumulate PHB granules inside their cells. Isolate AS-02 was isolated from cattle manure and identified as Bacillus wiedmannii AS-02 OK576278 by means of 16S rRNA analysis. It was found to be the best producer. The optimum pH, temperature, and incubation period for the best PHB production by the isolate were 7, 35 ◦ C, and 72 h respectively. PHB production was the best with peptone and glucose as nitrogen and carbon sources at a C/N ratio of (2:1). The strain was able to ac- cumulate 423, 390, 249, 158, and 144 mg/L PHB when pretreated orange, mango, banana, onion peels, and rice straw were used as carbon sources, respectively. The extracted polymer was characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and GC-MS spectroscopy, which confirmed the structure of the polymer as PHB. The isolate B. wiedmannii AS-02 OK576278 can be considered an excellent candidate for industrial production of PHB from agricultural wastes. Keywords: Polyhydroxybutyrates (PHBs); agricultural wastes; bioplastic; bacteria; 16S rRNA analysis; NMR 1. Introduction Plastic materials that have been generally used in our daily lives are now causing dangerous environmental problems. Millions of tons of these non-degradable plastics accumulate in the environment per year. Petroleum-based plastics have serious ecological and social impacts because of their non-degradable nature and the leaching of carcinogenic substances when exposed to scratch or heat [1]. Biopolymers are one type of product that can help to overcome problems caused by petrochemical polymers. Biopolymers are generated from renewable natural sources and are often biodegradable and nontoxic. They are either produced by biological systems (microorganisms, plants, and animals) or produced from substrates obtained from living organisms such as polylactic acid, which can be synthesized from biologically obtained lactic acid [2]. Among various biodegradable polymer materials are polyhydroxyalkanoates (PHAs) [3]. PHAs are thermoplastic aliphatic polyesters with linear polymer chains that are manufactured via a microbial process on sugar-based medium, where they act as carbon and energy storage material in bacteria. The main member of the PHAs family is polyhydroxybutyrate (PHB). It is accumulated in the cells as intracellular granules in the presence of excess carbon source or under differ- ent stress conditions, such as a limited amount of macro-components (nitrogen, phosphate, oxygen) or micro-components (sulfate, magnesium ions, and other trace elements) [4]. Microorganisms 2021, 9, 2395. https://doi.org/10.3390/microorganisms9112395 https://www.mdpi.com/journal/microorganisms