p-Hydroxybenzoic Acid (p-HBA) Bioproduction Engineering Service

p-Hydroxybenzoic Acid (p-HBA) is a valuable chemical intermediate used in the synthesis of pharmaceuticals, liquid crystal polymers, and parabens (preservatives). Industrial production via chemical synthesis involves high pollution and reliance on non-renewable petroleum feedstocks. While microbial biosynthesis offers a sustainable alternative, native pathways are often incomplete or lack the efficiency needed for commercial competition.

CD Biosynsis offers a synthetic biology service focused on engineering the microbial host Escherichia coli . Our core strategy involves the modification of the Escherichia coli shikimate pathway , a central route for aromatic amino acid synthesis, to maximize carbon flux towards the precursor, chorismate. This is combined with the overexpression of p-hydroxybenzoate synthase (p-HBA synthase) , the key enzyme that converts chorismate into the final p-HBA product. This integrated approach aims to deliver a high-yield, environmentally benign, and cost-effective bioproduction route for this essential chemical.

Pain Points

Transitioning p-HBA production from chemical to biological synthesis requires overcoming these technical challenges:

• Environmental Impact of Chemical Route: Traditional synthesis methods often involve high temperatures, harsh solvents, and generate hazardous waste streams , contradicting green chemistry principles.
• Incomplete/Inefficient Biosynthetic Pathways: Native microbial pathways often have low flux or are tightly regulated to only produce small amounts of p-HBA, as it's typically a minor intermediate or precursor.
• Precursor Diversion: The shikimate pathway is a hub. Carbon flux is easily diverted to competing pathways for the synthesis of essential amino acids (Phe, Tyr, Trp), limiting precursor availability (chorismate).
• Product Toxicity: High concentrations of p-HBA and related aromatic compounds can be toxic to the microbial host , inhibiting cell growth and productivity during fermentation.

A competitive solution must establish high carbon flux towards chorismate and minimize metabolic competition.

Solutions

CD Biosynsis utilizes advanced metabolic engineering to optimize p-HBA production in E. coli :

Modification of Escherichia coli Shikimate Pathway

           

We employ rational engineering to overexpress and de-regulate key rate-limiting enzymes (e.g., aroG⁽ᶠᵇʳ⁾) in the early shikimate pathway to maximize the supply of the chorismate precursor.

Overexpression of p-Hydroxybenzoate Synthase

We introduce and overexpress a highly active p-HBA synthase (UbiC) from a suitable source to ensure the rapid, efficient conversion of chorismate to p-HBA , minimizing precursor accumulation.

Competing Aromatic Pathway Knockout

We delete genes involved in the downstream synthesis of essential aromatic amino acids (Phe, Tyr, Trp) to redirect metabolic flow exclusively towards p-HBA production .

Efflux Pump or Excretion Optimization

We explore engineering or overexpressing specific efflux pumps or transporters to quickly move p-HBA out of the cell, reducing intracellular toxicity and sustaining high production rates.

This systematic approach is focused on establishing a robust, dedicated metabolic pipeline from simple carbon sources to p-HBA.

Advantages

Our p-HBA engineering service is dedicated to pursuing the following production goals:

Sustainable Production Route

Utilizes renewable feedstocks (sugars) and avoids hazardous chemical processes , aligning with green chemistry objectives.

Enhanced Carbon Yield

Pathway de-regulation and competing pathway knockout are focused on achieving a high molar yield of p-HBA from glucose.

Reduced Byproduct Formation

Dedicated pathways and high p-HBA synthase activity minimize the formation of unwanted aromatic byproducts , simplifying purification.

Simplified Product Recovery

Engineering for excretion (efflux) allows for continuous removal of p-HBA from the medium, potentially reducing downstream processing costs . [Image of Cost Reduction Icon]

High Fermentation Productivity

Using a fast-growing host like E. coli coupled with efflux optimization allows for high volumetric and specific productivity .

We provide a biosynthetic platform aimed at maximizing the yield and cost-effectiveness of sustainable p-HBA production.

Process

Our p-HBA strain engineering service follows a standardized, iterative research workflow:

• Precursor Pathway Engineering: Modify key enzymes (AroF}/\text{G}/\text{H) in the shikimate pathway for feedback inhibition resistance and overexpression , maximizing chorismate supply.
• Target Pathway Integration: Introduce and optimize the expression of the p-HBA synthase gene (UbiC) under a strong, inducible promoter for efficient conversion.
• Metabolic Byproduct Knockout: Delete genes responsible for the synthesis of competing aromatic amino acids and secondary metabolites that consume chorismate.
• Toxicity Mitigation: Engineer the host cell to overexpress p-HBA-specific efflux pumps or use in situ product removal methods to reduce cellular toxicity.
• Fermentation Performance Validation: Test the final engineered strain in fed-batch fermentation to assess volumetric productivity, final p-HBA titer, and yield .
• Result Report Output: Compile a detailed Experimental Report including genome modification data, enzyme expression data, and fermentation metrics (yield, titer, and productivity) , supporting process optimization and scale-up.

Technical communication is maintained throughout the process, focusing on timely feedback regarding precursor flux and product accumulation.

Explore the potential for a green, high-yield p-HBA synthesis route. CD Biosynsis provides customized strain engineering solutions:

• Detailed Metabolic Flux and Titer Analysis Report , illustrating the success of pathway de-regulation and final product accumulation.
• Consultation on fermentation strategies optimized for aromatic acid production and toxicity mitigation.
• Experimental reports include complete raw data on carbon yield (g p-HBA}/\text{g glucose) and product purity , essential for industrial adoption.