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Combining the enrichment and accumulation step in non-axenic PHA production: Cultivation of Plasticicumulans acidivorans at high volume exchange ratios

Paper ID Volume ID Publish Year Pages File Format Full-Text
22682 43369 2016 8 PDF Available
Title
Combining the enrichment and accumulation step in non-axenic PHA production: Cultivation of Plasticicumulans acidivorans at high volume exchange ratios
Abstract

•A one-stage process for simultaneous culture enrichment and PHB production.•Production of up to 75 wt% PHB from acetate in a non-axenic, single-step process.•Cultivation at very high volume exchange ratios compromises PHB production rate.•Increasing the volume exchange ratio forces bacteria to grow faster (at same SRT).

The process for non-axenic polyhydroxyalkanoate (PHA) production from organic waste generally comprises three steps: acidogenic fermentation of the waste stream, enrichment of a PHA-producing culture, and production of the PHA. This study assesses the feasibility of combining the enrichment and production step. Harvesting PHA-rich biomass directly from the sequencing batch reactor (SBR) used for enrichment of the microbial culture reduces capital cost, but may increase downstream-processing cost if the PHA content is significantly lowered. Operating an acetate-fed SBR at a volume exchange ratio of 0.75 (18 h cycles, 1 d SRT) allowed the production of biomass with 70 wt% poly(3-hydroxybutyrate) (PHB) in a single-step process. By increasing the exchange ratio to 0.83 (20 h cycles) the PHB content of the harvested biomass increased to 75 wt%, but the operational stability decreased. SBR operation at these high exchange ratios makes that bacteria have to increase their growth rate and external substrate is available for relatively long periods. This allows the establishment of larger flanking populations and negatively affected the kinetic properties of Plasticicumulans acidivorans, the predominant organism. Maximizing the volume exchange ratio is, therefore, a suitable strategy to produce large amounts of PHA in the SBR, but does not ensure the enrichment of a culture with superior PHA productivity.

Keywords
CL, cycle length; F/M ratio, food-to-microorganism ratio; HRT, hydraulic retention time; PHA, polyhydroxyalkanoate; PHB, poly(3-hydroxybutyrate); SBR, sequencing batch reactor; SRT, solids retention time; TSS, total suspended solidsCycle length; Microbial
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Combining the enrichment and accumulation step in non-axenic PHA production: Cultivation of Plasticicumulans acidivorans at high volume exchange ratios
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 231, 10 August 2016, Pages 260–267
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us