Production of polyhydroxybutyrate from oil palm empty fruit bunch (OPEFB) hydrolysates by Bacillus cereus suaeda B-001

Polyhydroxybutyrate (PHB) is a biodegradable polymer accumulated in intracellular granules by numerous bacteria. Its physical and chemical characteristics are like those of petrochemical plastics. PHB is produced mainly by gram-negative bacteria such as Ralstonia eutropha, which have lipopolysaccharides that co-purify with the PHB and cause immunogenic reactions, limiting their use for biomedical applications. PHB produced from gram-positive bacteria such as Bacillus spp. do not have lipopolysaccharides, which makes it suitable for biomedical application. The aim of this work was to evaluate the ability of Bacillus cereus suaeda B-001 to accumulate PHB using oil palm empty fruit bunch (OPEFB) hydrolysate as the sole carbon source, comparing it to commercial glucose as the control. OPEFB was chemically pre-treated using an acid-hydrolysed process by sulphuric acid and neutralized by a NaOH solution to obtain reducing sugars. PHB biopolyester accumulated to 43.1% of cell dry weight with glucose at 15 g/L as the sole carbon source, and PHB accumulated to 55.4% of cell dry weight using OPEFB hydrolysates at 20 g/L. The conversion of OPEFB acid hydrolysates to PHB using the gram-positive bacteria Bacillus cereus suaeda B-001 has not been reported.