Processes for producing L-cysteic acid along with uses for the same. The process includes providing a reaction of O-phospho-L-serine (OPS) with a salt of sulfurous acid (sulfite) and a cysteate synthase (CS enzyme) belonging to enzyme class EC 2.5.1.76 in a biotransformation. Where a concentration of OPS in a batch is at least 1 g/L and the CS enzyme is produced in an enzymatically active form by growth of the microorganism strain E. coli K12 JM105. The biotransformation is carried out under active pH control and the CS enzyme has an amino acid sequence specified in SEQ ID NO: 4 or an amino acid sequence homologous thereto. Where an amino acid sequence homologous to SEQ ID NO: 4 has a sequence identity of at least 50% in relation to SEQ ID NO: 4 and, at the same time, cysteate synthase enzyme activity.

Disclosed herein are polynucleotides comprising sequences encoding coenzyme M synthase (ComF) linked to a heterologous regulatory element and methods of using the same. The polynucleotides may comprise synthetic operons comprising additional sequences encoding enzymes, e.g., a taurine-pyruvate aminotransferase, a sulfoacetaldehyde acetyl transferase, or a sulfopyruvate decarboxylase. Also disclosed herein are recombinant prokaryotic cells, e.g., recombinant bacterial, e.g., E. coli, or archaeal cells, e.g., Methanosarcina acetivorans with improved tolerance to oxidative stress.

Methods for the fermentative production of O-phosphoserine, cysteate, or taurine in microbes or unicellular organisms that contain a serB mutation that either decreases serB expression, reduces the amount of the serB gene product or results in a serB gene product with low enzymatic activity. Genetic modifications of the O-phosphoserine, cysteate, or taurine and/or substrate biosynthetic pathways in unicellular organisms that include bacteria, algae, microalgae, diatoms, yeast, or fungi are disclosed. Also disclosed are fermentation and processing methods for the production of various O-phosphoserine-, cysteate-, or taurine-containing products and the use of the cells, fermentation broth or extracts that contain O-phosphoserine, cysteate, or taurine to produce products for use in food, feed, beverages, dietary and health supplements, cosmetics, personal care, pharmaceuticals, agricultural production, or surfactants.