# Chicken Manure as a Sustainable Bile Acid Source for Biotechnological Applications

## TL;DR

Chicken manure contains high amounts of bile acids that can be used to make UDCA, a drug used for gallstones and liver disorders.

## Contribution

Chicken manure is proposed as a novel and sustainable source of bile acids for biotechnological production of UDCA.

## Key findings

- Chicken manure contains high concentrations of chenodeoxycholic acid (CDCA), a precursor for UDCA.
- A Pseudomonas putida strain successfully converted CDCA from chicken manure into UDCA without prior purification.
- Fresh chicken manure samples showed the highest CDCA concentrations.

## Abstract

Ursodeoxycholic acid (UDCA) is widely administered to dissolve gallstones, treat liver disorders and reduce blood cholesterol levels. This study investigated fresh and dried chicken manure as a sustainable bioresource for chenodeoxycholic acid (CDCA), a precursor for the biotechnological production of UDCA. For this, bile acids from five commercial dried and seven fresh chicken manure samples were analysed. The bile acid pool consisted predominantly of CDCA (30%–90%) and 7‐keto lithocholic acid (7k‐LCA, 8%–56%), with minor amounts of cholic acid. CDCA concentrations varied between 62 and 2990 mg per kg dry weight, and the highest concentrations were found in two samples from fresh chicken manure, confirming that chickens can produce high but varying amounts of faecal CDCA. As a proof of principle, a newly created
Pseudomonas putida
KT2440 strain expressing a heterologous 7α−/7β‐hydroxysteroid dehydrogenase system was shown to be able to transform manure‐derived CDCA into UDCA without prior substrate purification from raw ethanolic chicken manure extracts. These results demonstrate that chicken manure can be used as an untapped resource for bile acids for biotechnological applications, providing a novel approach for the valorisation of this bioresource.

This study highlights that chicken manure represents an abundant but untapped resource for bile acids, which are in high demand for pharmaceutical and biotechnological applications. We further show that the predominant bile acid, chenodeoxycholic acid, can be used directly from ethanolic manure extracts to produce pharmaceutically relevant ursodeoxycholic acid.