This research investigates the biosynthesis optimization of the red pigment prodigiosin produced by Serratia marcescens 11E through submerged fermentation utilizing an alternative cheese whey-based medium, focusing on process parameters and antimicrobial properties. Four types of whey sourced from a local dairy industry were characterized, and the fermentation conditions were optimized using Plackett–Burman and central composite design methodologies, yielding up to 1.43 g/L of prodigiosin under optimal conditions, 25 °C, 200 rpm, pH 7, and 48 h of dark incubation, with whey serving as the sole carbon source. Normalization to biomass yielded 110 mg of prodigiosin per gram of dried cell weight (post-optimization), enabling meaningful comparison with prior studies. Pigment extraction was performed with acidic methanol, and identity was confirmed by UV–Vis spectrophotometry and Fourier transform infrared spectroscopy (FTIR). The antimicrobial activity of the purified pigment was also evaluated. Although cheese whey has significant nutritional value, nearly half of the global production is discarded due to high treatment costs. This study demonstrates that whey can be repurposed as a sustainable and economical fermentation medium for pigment production, which is compatible with dairy plants. This makes it a promising solution to address the underutilization of whey by cheese local producers in Mexico. Prodigiosin has diverse industrial applications, including antimicrobial, insecticidal, and antioxidant properties. These findings highlight the potential for dairy waste valorization in a circular bioeconomy, reducing environmental impacts and promoting the creation of valuable bioproducts.

Lipolytic and esterase-like enzymes are crucial in the food industry for flavor production and ester hydrolysis. This study presents an exploratory, baseline feasibility approach to evaluate esterase-like enzyme production by Serratia marcescens 11E via a sustainable co-valorization matrix, where vegetable wax residues serve as structural solid support and cheese whey acts as the primary lipid nutritional source. Under fixed 48-h screening conditions, the recovered cell-free extract exhibited a distinct catalytic preference for short-chain esters, showing higher specific activity toward 4-nitrophenyl acetate (0.743 U/mg) than 4-nitrophenyl palmitate (0.125 U/mg), confirming a predominant carboxylesterase-like profile. Biochemical characterization revealed an initial optimal activity at pH 9.0 and 30 °C, along with a noteworthy bimodal catalytic behavior featuring a secondary activity peak at 70 °C. Size-exclusion chromatography resolved the extract into two distinct active elution pools (17.8 and 26.2 U/mg), which corresponded to candidate protein bands of 35–40 kDa on SDS-PAGE. Although definitive molecular identification remains subject to ongoing zymographic and proteomic characterization, these foundational findings demonstrate the potential of co-valorizing lipid- and carbohydrate-rich industrial wastes to produce resilient proteins with esterase-like activity at elevated temperatures.

Lipolytic enzymes play a crucial role in the food industry, aiding in cheese ripening, ester hydrolysis, and flavor production. Utilizing waste residues through low-cost, energy-efficient methods enables the synthesis of high-value commercial compounds. This research assessed lipolytic enzyme production by Serratia marcescens 11E using solid-state fermentation (SSF), with residual cheese whey and vegetable wax as solid supports. After 48 hours, the crude extract exhibited higher activity toward 4-nitrophenyl acetate (0.743 U/mg) than 4-nitrophenyl palmitate (0.125 U/mg), indicating esterase activity. Biochemical analysis indicated optimal conditions at pH 9.0 and 30 °C, with a secondary activity peak at 70 °C, suggesting the presence of isoforms supported by SDS-PAGE bands at 35 and 40 kDa. Size-exclusion chromatography separated two peaks with specific activities of 17 and 26 U/mg, demonstrating the potential of lipid-rich industrial waste for producing thermally stable esterases, thus advancing more sustainable biotechnological application processes.