Recent Advances in the Biosynthesis of Polyhydroxyalkanoates from Lignocellulosic Feedstocks

Abstract

Polyhydroxyalkanoates (PHA) are biodegradable polymers that are considered able to replace synthetic plastic because their biochemical characteristics are in some cases the same as other biodegradable polymers. However, due to the disadvantages of costly and non-renewable carbon sources, the production of PHA has been lower in the industrial sector against conventional plastics. At the same time, first-generation sugar-based cultivated feedstocks as substrates for PHA production threatens food security and considerably require other resources such as land and energy. Therefore, attempts have been made in pursuit of suitable sustainable and affordable sources of carbon to reduce production costs. Thus, in this review, we highlight utilising waste lignocellulosic feedstocks (LF) as a renewable and inexpensive carbon source to produce PHA. These waste feedstocks, second-generation plant lignocellulosic biomass, such as maize stoves, dedicated energy crops, rice straws, wood chips, are commonly available renewable biomass sources with a steady supply of about 150 billion tonnes per year of global yield. The generation of PHA from lignocellulose is still in its infancy, hence more screening of lignocellulosic materials and improvements in downstream processing and substrate pre-treatment are needed in the future to further advance the biopolymer sector.

Versatile aliphatic polyester biosynthesis system for producing random and block copolymers composed of 2-, 3-, 4-, 5-, and 6-hydroxyalkanoates using the sequence-regulating polyhydroxyalkanoate synthase PhaCAR

“…PHA biosynthesis systems have several advantages over ROP. PHAs are produced via a one-step fermentation process from different feedstock [ 9 , 10 ]. PHA synthases possess strict enantio-specificity and synthesize isotactic polymers [ 11 ].…”

The Hyperproduction of Polyhydroxybutyrate Using Bacillus mycoides ICRI89 through Enzymatic Hydrolysis of Affordable Cardboard

“…A reasonable content of PHA was successfully produced using 3 different algal hydrolysates media from Halomonas pacifica ASL10 and Halomonas salifodiane ASL11 [ 9 ]. Since the issue of PHA commercialization has not been resolved, affordable alternative carbon sources, such as the use of agricultural waste [ 10 ], household waste [ 11 ], fats, oils, industrial by-products [ 12 ], glycerol, sugars, wastewater, and lignocellulosic materials [ 13 ], have been considered.…”

A fermentation process for the production of poly(3-hydroxybutyrate) using waste cooking oil or waste fish oil as inexpensive carbon substrate

“…The price of the carbon substrate used in the PHA production process is a major reason, contributing up to 50% of the total production cost [ 11 , 12 ]. Hence, the utilization of inexpensive and renewable carbon substrates such as agricultural or industrial residues is offering a main solution for reducing PHA production cost [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] .…”