Bacterial production of PHA from lactose and cheese whey permeate

Abstract

Due to the large availability of agro-industry wastes containing potentially exploitable substrates, such as whey from dairy industry, a study on the bacterial conversion of lactose and whey permeate to poly(β-hydroxyalkanoate) (PHA) was undertaken. A first approach was carried out on culture collection strains. Among a number of strains tested, Hydrogenophaga pseudoflava DSM 1034 and Sinorhizobium meliloti 41 were found to grow on lactose and produce PHA. These findings suggested to investigate among a wider range of microorganisms by directly isolating new strains from soil. A number of soil bacteria were first isolated on a minimal medium containing lactose as unique carbon source and PHA-accumulating traits were then investigated. Three isolates, identified by 16S rDNA sequence analysis as Sinorhizobium sp., Bacillus megaterium and Bacillus sp., were selected for their efficient growth and PHA production using lactose as carbon source. The same strains were also tested for their ability to accumulate PHA by direct fermentation of whey and whey permeate. Our results suggest that production of the polymer from cheese whey or whey permeate may be possible, although further research is needed to determine whether these microorganisms have the potential for commercial production of such biodegradable polymers

Comparing Chemical and Enzymatic Hydrolysis of Whey Lactose to Generate Feedstocks for Haloarchaeal Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) Biosynthesis

“…The same terpolyester was also produced by H. pseudoflava using lactose or sucrose plus additional supplementation of yeast extract. These findings were in contrast to previous results from the same group [24] and our own works [17], where recovered PHA samples from whey-and lactose based cultivation of H. pseudoflava contained 3HB as the only monomeric building block. Based on these findings, Povolo et al [25] assumed that one or more unknown components, present in both yeast extract and in whey, might cause 4HB production and its following incorporation into the biopolyester.…”

“…Hence, new (bio) products from whey are aspired, especially such as those produced by the action of either Gram-positive or Gram-negative microbial production strains [16,23]. Investigation of whey-based PHA biosynthesis started almost 20 years ago and encompassed the implementation of both Gram-negative wild type strains like Haloferax mediterranei [17], Sinorhizobium meliloti [24], Hydrogenophaga pseudoflava [17,24,25], Pseudomonas hydrogenovora [18], or Methylobacterium sp. [26], and genetically engineered Gram-negative organisms, predominately Escherichia coli [27,28] and Cupriavidus necator [29].…”

Poly(hydroxyalkanoate) Production by Cupriavidus necator from Fatty Waste Can Be Enhanced by phaZ1 Inactivation

“…Since almost 50 % of the total production costs can be attributed to the carbon source for microbial growth and polymer production, the selection of renewable, cheap carbon feedstock, specially generated from industrial or agricultural by-products, can provide a way to reduce the price 6,7,8 . To that end, different industrial by-products, such as whey 9,10 , molasses 11 , starch, and waste oils and glycerol, have been investigated as start materials for PHA production 12,13,14,15 . In this perspective, fatty residues from slaughterhouse represent a promising raw material.…”

Whey Lactose as a Raw Material for Microbial Production of Biodegradable Polyesters

“…In literature, the production of bioethanol (Ghaly & El-Taweel, 1997;Zafar & Owais, 2006), vinegar (Parrondo et al, 2003), antibiotics, e.g. the bacteriocin Nisin, (Hickmann Flôres & Monte Alegre, 2001), yeasts for yeast extract production ( de Palma Revillion et al, 2003), surface active compounds like sophorolipids (Daniel et al, 1999), single-cell protein (Schultz et al, 2006), "green bioplastics" like Polyhydroxyalkanoates, PHAs, (Ahn et al, 2000;Ahn et al, 2001;Kim, 2000;Povolo & Casella, 2003;Koller et al, 2007 a,b), and lactic acid that is of importance as food additive (E 270), for pharmaceutical matrices, and as monomer for the production of polylactic acid (PLA) is described (Kim et al, 1995). In addition, the induction of high-celldensity production of recombinant proteins can be accomplished by providing whey (Viitanen et al, 2003).…”

“…In batch mode, final PHB concentrations of 2.07 g/L with 67% of PHB in biomass and 0.06 g/L h of volumetric PHB productivity are reported. Povolo & Casella (2003) reported the production of PHA from lactose by Paracoccus denitrificans DSM 413, Sinorhizobium meliloti 41 and Hydrogenophaga pseudoflava DSM1034. The latter two strains were also able to produce the polymer directly from cheese whey permeate and especially Hydrogenophaga pseudoflava turned out to be a promising candidate for PHA production from whey.…”