Chitosan-harvested polyhydroxybutyrate-rich Zobellella denitrificans ZD1 as a multifunction feed for aquaculture

Polyhydroxyalkanoates for Sustainable Aquaculture: A Review of Recent Advancements, Challenges, and Future Directions

“…For example, a significant inhibitory effect of PHB intermediates/SCFAs (3-HB and butyrate) on G− pathogens (V. campbellii and A. hydrophila) than on G+ strain (S. agalactiae) was observed. 33 Similarly, PHA intermediates (either SCFAs: butyrate and valerate or MCFAs: hexanoate and octanoate) were more effective against G-aquaculture pathogens (V. campbellii and A. hydrophila) than G+ S. agalactiae. 32 This stronger inhibition activity of PHA intermediates against G− strains is likely attributed to the higher diffusion of the intermediates through the thin peptidoglycan layer of G− cell wall, while hindered by the thick peptidoglycan layer of G+ strains.…”

“…Notably, chitosan-harvested PHB-rich SCPs have proven to serve as an efficient biocontrol agent, a feed/energy source, and an immunostimulant, contributing to sustainable aquaculture. 33 In the case of BFT, a pond-based BFT was upgraded by introducing sequencing batch reactors (SBRs) as an external compartment of the BFT (as indicated in Table 1). 122 This innovative approach achieved significant nitrogen removal efficiency (98%) due to the presence of heterotrophic microbial biomass, which utilized glycerol or acetate as a C source at an optimal C/N ratio of 10 and 15.…”

“…20,34 Overall, there are four main mechanisms for PHB beneficial impacts: 20 (i) inhibiting the growth of pathogenic bacteria 6,30,31 and/or suppressing virulence factors, 50 (ii) enhancing the immune system by stimulating stress-and immune-related genes in the supplemented animals, [34][35][36][37][38]48 (iii) serving as an energy source for aquatic animals, 31,152 and (iv) shaping a healthier gut microbiome. 33,35,39,40,77 6.2.1. PHB Inhibition of Pathogen Growth and Virulence Factors.…”

“…6,20 Supplementing aquafeeds with PHB in crystalline form (i.e., extracted from microbial proteins/biomass) or amorphous form (i.e., PHB-containing cells) has been shown to improve growth and disease resistance in many fish species and crustaceans by inhibiting pathogen growth, 6,30−33 reducing pathogen virulence factors, enhancing the immune system, 33−38 providing energy to aquatic animals, 20,32−34 and improving the beneficial microbes in the gut microbiota. 33,35,39,40 Accordingly, one can use PHBproducing microorganisms to grow on different renewable waste-derived substrates and produce PHB-rich microbial proteins as healthy aquafeed. Such microorganisms, used as an aquaculture feed, are also called single-cell proteins (SCPs) or microbial proteins because they are rich in proteins and contain readily digestible nutrients (e.g., lipids and minerals).…”

Ovation of biopolymers in conterminous EU members via clustering of biotechnological advances : A mini-compendium

“…Pioneering work in genomics has also made possible the industrial stance regarding advanced bioproducts. Synthetic biology demonstrates the shrewdness of the biotech industry in embedding laboratory techniques and leveraging data and technologies ( Zheng et al, 2020 ; Asiri et al, 2022 ).…”