Engineering a predatory bacterium as a proficient killer agent for intracellular bio-products recovery: The case of the polyhydroxyalkanoates

Abstract

This work examines the potential of the predatory bacterium Bdellovibrio bacteriovorus HD100, an obligate predator of other Gram-negative bacteria, as an external cell-lytic agent for recovering valuable intracellular bio-products produced by prey cultures. The bio-product targets to be recovered were polyhydroxyalkanoates (PHAs) produced naturally by Pseudomonas putida and Cupriavidus necator, or by recombinant Escherichia coli strains. B. bacteriovorus with a mutated PHA depolymerase gene to prevent the unwanted breakdown of the bio-product allowed the recovery of up to 80% of that accumulated by the prey bacteria, even at high biomass concentrations. This innovative downstream process highlights how B. bacteriovorus can be used as a novel, biological lytic agent for the inexpensive, industrial scale recovery of intracellular products from different Gram-negative prey cultures.

Recent Advances and Challenges towards Sustainable Polyhydroxyalkanoate (PHA) Production

“…When the lytic cycle is completed, the virus escapes from the host cell by breaking down the cell wall; this breaking down also liberates the PHA particles allowing their recovery [ 162 ]. In recent years, biological disruption methods included bacteria predators, rats, and mealworms [ 178 , 179 , 180 ].…”

Biotechnological Potential of Bdellovibrio and Like Organisms and Their Secreted Enzymes

“…Using the PhaZ Bd -deficient strain resulted in the recovery of >80% of the PHA accumulated in the prey cells, compared to 54-60% with the wild type strain. These results have encouraged further investigation, potentially providing a system for harvesting bioproducts such as PHA in one step, reducing the industrial use of detergents and solvents (Martínez et al, 2016).…”

Beyond Intracellular Accumulation of Polyhydroxyalkanoates: Chiral Hydroxyalkanoic Acids and Polymer Secretion

“…Another strategy for the recovery of PHAs is the use of external cell lytic agents such as the Bdellovibrio bacteriovorus HD100 bacterium, an obligate predator of other gramnegative bacteria which acts as a lithic agent for the recovery of intracellular bioproducts of industrial interest (Martínez et al, 2016). B. bacteriovorus HD100 was genetically modified by eliminating the PHA depolymerase gene in order to prevent the breakdown of the recovered PHAs.…”