Synthesis of polyhydroxyalkanoate from palm oil and some new applications

Abstract

Polyhydroxyalkanoate (PHA) is a potential substitute for some petrochemical-based plastics. This biodegradable plastic is derived from microbial fermentation using various carbon substrates. Since carbon source has been identified as one of the major cost-absorbing factors in PHA production, cheap and renewable substrates are currently being investigated as substitutes for existing sugar-based feedstock. Plant oils have been found to result in high-yield PHA production. Malaysia, being the world's second largest producer of palm oil, is able to ensure continuous supply of palm oil products for sustainable PHA production. The biosynthesis and characterization of various types of PHA using palm oil products have been described in detail in this review. Besides, by-products and waste stream from palm oil industry have also demonstrated promising results as carbon sources for PHA biosynthesis. Some new applications in cosmetic and wastewater treatment show the diversity of PHA usage. With proper management practices and efficient milling processes, it may be possible to supply enough palm oil-based raw materials for human consumption and other biotechnological applications such as production of PHA in a sustainable manner.

Polyhydroxyalkanoate Synthesis by Recombinant Escherichia coli JM109 Expressing PHA Biosynthesis Genes from Comamonas sp. EB172

“…The results showed that both CDW and PHA content were improved, when the fermentation was supplemented with (NH 4 ) 2 SO 4 . This indicates that PHA biosynthesis in recombinant E. coli happened during growth, and not under nutrient limitation like those phenomenon observed in wild type PHA producer such as C. necator [31].…”

“…Hence, the CDW and PHA content in the cells can be improved under regular carbon and nitrogen supplement in recombinant cells. 4 supplemented with 50 µg/mL of ampicillin. Sterilized glucose was added during inoculation, while mixed acids were supplied directly prior to autoclaving and pH was adjusted using 1M NaOH.…”

“…Moreover, the addition of nitrogen was able to increase the CDW and PHA accumulation, using glucose in the medium as substrate. 4 supplemented with 50 µg/mL of ampicillin. Sterilized glucose was added during inoculation, while mixed acids were supplied directly, prior to autoclaving and pH was adjusted using 1M NaOH.…”

“…The MS medium consisted of (in g/L) 5 g KH 2 PO 4 , 2 g K 2 HPO 4 , 1 g (NH 4 ) 2 SO 4 , 0.4 g MgSO 4 •7H 2 O and 1 mL of trace element solution [17]. Ampicillin (50 µg/mL) was added, when it was necessary for plasmid maintenance.…”

“…Polyhydroxyalkanoates (PHAs) are energy storage, hydrophobic granules that can be accumulated by many microorganisms [1][2][3][4]. PHAs are biodegradable, biocompatible thermoplastics, and hence, these biopolyesters are not only the potential alternative candidates for recalcitrant synthetic plastics, but also present long-term benefits for environmental pollution issues.…”