PHA Production from Organic Waste via VFA Filtration
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Solution Overview
Problem
Current commercial PHA production relies on sugar- or plant oil-based feedstocks, which are costly and raise issues of land use competition with food production, and do not effectively utilize organic waste, which is a potential low-cost alternative that can divert waste from landfills and reduce greenhouse gas emissions.
Innovation Solution
A method involving the homogenization of organic waste with a 1:1 to 3:1 water to organic waste ratio, inoculation with acidogenic fermentative bacteria, incubation to produce volatile fatty acids, and subsequent filtration to concentrate these acids for use by high-PHA producing bacteria, allowing for the production of intracellular PHA granules and subsequent extraction of PHA polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sugar- or plant oil-based feedstocks are used for PHA production, then PHA can be produced with established methods, but production costs are high and land use competes with food production
Solution Approach 1:
The patent uses inexpensive organic waste materials (food waste, agricultural residues, municipal solid waste) as feedstock instead of expensive sugar or plant oil-based substrates. These waste materials are typically discarded or underutilized, making them economically attractive and sustainable alternatives that reduce production costs while avoiding land-use conflicts with food production
Solution Approach 2:
The patent employs pretreatment parameters (thermal, chemical, or enzymatic treatment) to convert complex organic waste structures into bioavailable forms that microorganisms can efficiently utilize. By adjusting pretreatment conditions such as temperature, pH, and treatment duration, the system optimizes the conversion of recalcitrant organic waste into fermentable substrates for PHA production
2Quantity of substance
If organic waste is used as feedstock, then production costs decrease and waste diversion from landfills increases, but organic waste requires additional hydrolysis and acidogenesis processing steps
Solution Approach 1:
The patent divides the complex organic waste conversion process into distinct sequential stages: pretreatment (hydrolysis), acidogenesis (VFA production), and PHA synthesis. Each stage uses specialized microorganisms optimized for its specific function, allowing independent optimization and control of each step while maintaining overall process efficiency
Solution Approach 2:
The patent introduces volatile fatty acids (VFAs) as an intermediary substance that bridges the pretreatment stage and the PHA production stage. Acidogenic bacteria convert organic waste into VFAs, which then serve as the carbon source for PHA-producing bacteria. This intermediary simplifies the overall process by creating a well-defined substrate for the final production stage
3Ease of operation
If organic waste is sent to landfills, then waste disposal is simplified, but greenhouse gas emissions increase significantly
Solution Approach 1:
The patent converts organic waste that would otherwise decompose anaerobically in landfills and generate methane (a potent greenhouse gas) into a valuable resource for PHA production. By diverting organic waste from landfills and processing it through controlled biological conversion, the system transforms a harmful emissions source into a sustainable feedstock for bioplastic production
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the efficient conversion of organic waste into PHA polymers, reducing production costs and environmental impact by utilizing waste materials, while achieving high yields and purity of PHA polymers.
Implementation Method 1
Before use as a feedstock for PHA production, organic waste must undergo hydrolysis and acidogenesis. During this process, controlled mixed microbial cultures convert the organic waste into volatile fatty acids (VFAs)
Implementation Method 2
The fermentation broth is filtered with a filter with a pore size ranging from 0.2 μm to 500,000 NMWC, optionally 0.2 μm to 300,000 NMWC, to remove the acidogenic fermentative bacteria and undigested organic waste
Implementation Method 3
PHAs are synthesized as an intracellular energy storage mechanism in a wide range of bacterial species. Biosynthesis of PHA can be induced by subjecting PHA-producing microbes to carbon-rich and nitrogen- and phosphorous-limiting conditions
Data Source
AI summary
According to one broad aspect of this disclosure, a method is provided for producing polyhydroxyalkanoates (PHA) from organic waste. The method comprises homogenizing organic waste to obtain a feedstock that has 1:1 to 3:1 (w/w) water to organic waste ratio. The feedstock is inoculated with an inoculum of acidogenic fermentative bacteria in order to obtain an inoculated feedstock. The inoculated feedstock is incubated for 5 to 10 days, 3 to 10 days, optionally 7 days, optionally 3 days, to obtain a fermentation broth. The fermentation broth comprises volatile fatty acids (VFAs) and undigested organic waste. The fermentation broth is filtered with a filter with a pore size ranging from 0.2 μm to 500,000 NMWC to remove the acidogenic fermentative bacteria and undigested organic waste, to obtain a clarified broth comprising concentrated VFAs. The clarified broth and high-PHA producing bacteria are incubated to produce intracellular PHA granules in the high-PHA producing bacteria. PHA polymers are extracted from the intracellular PHA granules.