Biosynthesis of Polyhydroxyalkanaotes by a Novel Facultatively Anaerobic Vibrio sp. under Marine Conditions

Abstract

Marine bacteria have recently attracted attention as potentially useful candidates for the production of practical materials from marine ecosystems, including the oceanic carbon dioxide cycle. The advantages of using marine bacteria for the biosynthesis of poly(hydroxyalkanoate) (PHA), one of the eco-friendly bioplastics, include avoiding contamination with bacteria that lack salt-water resistance, ability to use filtered seawater as a culture medium, and the potential for extracellular production of PHA, all of which would contribute to large-scale industrial production of PHA. A novel marine bacterium, Vibrio sp. strain KN01, was isolated and characterized in PHA productivity using various carbon sources under aerobic and aerobic-anaerobic marine conditions. The PHA contents of all the samples under the aerobic-anaerobic condition, especially when using soybean oil as the sole carbon source, were enhanced by limiting the amount of dissolved oxygen. The PHA accumulated using soybean oil as a sole carbon source under the aerobic-anaerobic condition contained 14% 3-hydroxypropionate (3HP) and 3% 5-hydroxyvalerate (5HV) units in addition to (R)-3-hydroxybutyrate (3HB) units and had a molecular weight of 42 × 10³ g/mol. The present result indicates that the activity of the beta-oxidation pathway under the aerobic-anaerobic condition is reduced due to a reduction in the amount of dissolved oxygen. These findings have potential for use in controlling the biosynthesis of long main-chain PHA by regulating the activity of the beta-oxidation pathway, which also could be regulated by varying the dissolved oxygen concentration.

Production, optimization and characterization of polyhydroxybutyrate, a biodegradable plastic by Bacillus spp.

“…In this regard, there are many reports of the use of terrestrial bacteria for bioplastic production. [27][28][29][30][31] However, the reports are scanty from the marine environment sources. 32) In comparison to terrestrial environment, marine sources are the less explored environmental conditions for the microbial diversity as well as the screening of potential marine bacteria.…”

Biosynthesis of Polyhydroxyalkanoate by a Marine BacteriumVibriosp. Strain Using Sugars, Plant Oil, and Unsaturated Fatty Acids as Sole Carbon Sources

“…Lee and coworkers reported that the reduction in dissolved oxygen concentration from 40% to 5% inhibited cell growth of recombinant Escherichia coli harboring PHA-synthesis genes and enhanced PHA contents from 10 to 27 wt% (21), demonstrating that PHA production could be enhanced under conditions similar to the aerobic-anaerobic ones used here. In our study, the strain cultured under the aerobic-anaerobic condition demonstrated constant cell growth irrespective of whether glucose, fructose or gluconate was used as the sole carbon source ( Table 2) (20). Here, an aerobic-anaerobic condition denotes that the strain was prepared and sealed under nitrogen atmosphere and cultured.…”

“…KN01, was investigated with respect to PHA productivity from well-known carbon sources, namely, glucose, fructose or gluconate at 30°C for 48 h under an aerobic condition (Table 2) (20). The strain exhibited cell growth ranging from approximately 1.4 to 1.7 g/L.…”

“…Recently, a novel type of marine bacterium, Vibrio sp. strain KN01 (Figure 1), was isolated and characterized with respect to its PHA productivity using various carbon sources under aerobic and aerobic-anaerobic marine conditions (20). In this minireview, we provide our recent works of PHA production by marine bacteria, based on the results of feeding experiments on the strain KN01, using sugars, plant oils and unsaturated fatty acids as sole carbon sources.…”

Poly(3-Hydroxypropionate): a Promising Alternative to Fossil Fuel-Based Materials

“…Only Vibrio sp. KN01 was able to synthesize the terpolymer consisting of 14 mol% 3HP, 83 mol% 3HB, and 3 mol% 5HV from soybean oil (productivity [P PHA ], 3.3 mg PHA liter Ϫ1 h Ϫ1 ) under aerobic or anaerobic conditions (46).…”