Bioconversion of novel and renewable agro-industry by-products into a biodegradable poly(3-hydroxybutyrate) by marine Bacillus megaterium UMTKB-1 strain

Abstract

Agro-industry by-products are abundant in various valuable compounds. Some of these raw materials are considered as a cheaper carbon source for polyhydroxyalkanoate (PHA) production when compared with pure substrates. It is however often a costly affair for industries to recover the residual carbon components. In this study, poly(3-hydroxybutyrate) [P(3HB)] was produced using a marine Bacillus megaterium UMTKB-1 strain from sweetwater, a by-product from cane sugar refining process. The bioconversion was initiated in shaken-flasks and fermenter experiments. Applications of seawater and sweetwater mixture as well as sweetwater only as PHA culture media were investigated. The produced polymer was characterized using Gas Chromatography (GC) and Gel Permeation Chromatography (GPC). P(3HB) accumulation from tested carbon sources ranged from 3 to 49 wt%. The strain could accumulate P(3HB) in saline conditions when minimal salts medium was replaced with seawater and sweetwater. The P(3HB) content was between 7 and 27 wt%. This strain was also able to grow and accumulate up to 14 wt% P(3HB) when sweetwater was the sole PHA biosynthesis medium. The weights of P(3HB) produced was in the range 3-12 × 10 5 with polydispersity index values ranging from 2.7 to 3.8. The agroindustry by-products have proven to be potential carbon feedstocks for P(3HB) production. The tested strain was able to grow and accumulate P(3HB) in a novel carbon substrate medium, the sweetwater. This by-product could be used as a raw material for P(3HB) production without any pretreatment.

Recent Advances in the Biosynthesis of Polyhydroxyalkanoates from Lignocellulosic Feedstocks

“…PHA has been commonly generated from municipal wastewater, solid waste, and cheese whey [52,66], waste cooking oil [57,[67][68][69], cane molasses [70], spent coffee grounds [71], phenol [72], food waste [73], sweetwater, a by-product of processing sugar cane [74], nonfood crops such as ryegrass [75], and agro-industrial waste [59]. Although various wastes have been reported to be recoverable to PHA, agricultural crop residues are the most available and investigated carbon substrate that helps in the growth of bacteria culture and PHA production [73]. The main focus that Pakalapati et al showed was on transforming rural, food-derived waste and industrial into PHA [15].…”

Fed-batch production and characterization of polyhydroxybutyrate by Bacillus megaterium LVN01 from residual glycerol

“…On the other hand, commercial PHA production is mainly focused on the use of Gram-negative bacteria (e.g., Cupriavidus, Pseudomonas, and E. coli) [9]. Nonetheless, these bacteria have endotoxins (lipopolysaccharides, LPS), which are released in the biopolymer extraction processes and affect their subsequent application in some areas of the industry (e.g., medical and pharmaceutical), thus requiring additional stages of purification [10].…”

Dataset on controlled production of polyhydroxyalkanoate-based microbead using double emulsion solvent evaporation technique

“…The strains used in this experiment were Massilia haematophila UMTKB-2, isolated from brackish water in Mengabang Telipot, Kuala Terengganu, Terengganu, Malaysia [5] and Bacillus megaterium UMTKB-1, isolated from the tissue sample of marine sponges collected from Pulau Langkawi, Kedah, Malaysia [6] . Bacillus megaterium UMTKB-1 was employed to synthesize homopolymer P(3HB), while Massilia haematophila UMTKB-2 was employed to synthesize copolymer P(3HB- co -3HV).…”

“…Bacillus megaterium UMTKB-1 and Massilia haematophila UMTKB-2 were first cultured into a sterile NR medium using shaken flask cultivation method for 14 and 12 h respectively to activate the cells at 200 rotations per minute (rpm) until the mid-exponential growth phase, after which the growth phase was determined by measuring the optical density of the bacterial culture at 600 nm. The biosynthesis, harvesting and recovery of P(3HB) was carried out according to Yatim and co-workers using sweet water [6] , whereas the biosynthesis, harvesting and recovery of P(3HB- co -3HV) was performed according to Kiun and co-workers [5] . Inactivation and removal of endotoxins from the polymers were performed using hydrogen peroxide, after which the endotoxin levels were tested using E-TOXATE™ Kits (Sigma Aldrich) [7] .…”