Use of waste materials for Lactococcus lactis development

Area of Science:

• Microbiology
• Biotechnology
• Industrial Microbiology

Background:

• Lactococcus lactis is a valuable microorganism in the food industry, known for its probiotic properties and production of lactic acid (LA) and biosurfactants.
• L. lactis has significant nutritional requirements, necessitating complex and costly culture media for optimal growth and metabolite production.

Purpose of the Study:

• To investigate the potential of using low-cost waste materials as alternative culture media for L. lactis.
• To reduce the economic burden associated with L. lactis cultivation for LA and biosurfactant production.

Main Methods:

• Utilized trimming vine shoots as a carbon source and distilled wine lees (vinasses) as a source of nitrogen, phosphorus, and micronutrients for L. lactis CECT-4434 cultures.
• Employed both direct fermentation of the hemicellulosic fraction and a simultaneous saccharification and fermentation (SSF) process.

Main Results:

• Achieved production of 14.3 g/L LA and 1.7 mg/L surfactin equivalent from the hemicellulosic fraction after 74 hours, with a surface tension reduction of 14.4 mN/m.
• The SSF process yielded 10.8 g/L LA and 1.5 mg/L surfactin equivalent after 72 hours, reducing surface tension by 12.1 mN/m.

Conclusions:

• Trimming vine shoots and vinasses are viable and economical alternatives to traditional media for producing LA and cell-bound biosurfactants.
• This research offers a sustainable approach to microbial metabolite production by valorizing agricultural waste streams.