Laktobionskābes ieguves biotehnoloģiskie risinājumi = The biotechnological solutions for lactobionic acid production
Authors:   ,   Latvia University of Life Sciences and Technologies, Sarenkova Inga 
Published: June 2022

The study has been caried out in the period from 2017 to 2022 in the research laboratories of the Latvia University of Life Sciences and Technologies: Scientific laboratory of microbiology, Dairy pilot-plant, Pilot-plant for fruit and vegetable processing, Laboratory of processes and equipment, Laboratory of nutrition and Scientific laborotory of chemistry of natural substances. Also, the research has been done in the laboratories of Scientific and Technological Resources at the University of Oviedo (Spain): food technology, cytometry and pilot-plant, as well as in the laboratories of the Department of Chemical and Environmental Engineering at the University of Oviedo (Spain). The hypothesis of the doctoral thesis: acid whey is suitable for lactobionic acid production by microbial fermentation. The hypothesis of the doctoral thesis is approved by the defended theses. 1. The composition of acid whey is suitable for the growth of Pseudomonas taetrolens; 2. The lactose concentration in acid whey is sufficient for lactobionic acid production; 3. The acid whey pH is adjustable for Pseudomonas taetrolens growth and modified conditions of the substrate have an influence on the metabolic activity of bacteria and lactose conversion into lactobionic acid; 4. The developed lactobionic acid technology is suitable for its application on a commercial scale. The objective of the doctoral thesis is to study the possibility of acid whey fermentation with Pseudomonas taetrolens for lactobionic acid production. The tasks of the doctoral thesis are. 1. To compile the available scientific resources on lactobionic acid production methods and their efficiency; 2. To choose technological solutions for economical lactobionic acid production from acid whey; 3. To evaluate the changes of lactose concentration during substrate’s fermentation; 4. To analyse the effect of fermentation parameters on higher lactobionic acid production. The thesis is performed into three chapters. Chapter 1. Review of the literature with the theoretical substantiation of the studied problem. Characteristics and application of lactobionic acid. Possibilities of lactobionic acid production. Pseudomonas taetrolens lactose bioconversion ability. Possibilities of lactobionic acid purification. Acid whey suitability for lactobionic acid production. Chapter 2. Characteristics of materials and methods used in the study, mathematical data processing. Chapter 3. Results on an effect of pH on lactobionic acid production. Effect of whey solids concentration on lactobionic acid production. Effect of different salts on lactobionic acid production. Comparison of different whey fermentation at controlled and uncontrolled pH in flasks and bioreactor. Comparison of different whey for lactobionic acid production. Production of lactobionic acid by re-addition of bacteria biomass. Products obtained after purification. The doctoral thesis is written in Latvian, on 113 pages, it includes 15 tables, 50 figures, 163 literature sources, and 3 appendices. The study has been financially supported by the grants: • Strengthening Research Capacity in the Latvia University of Life Sciences and Technologies. Project No Z23 “The biotechnological solutions for lactobionic acid production”; • Latvia University of Life Sciences and Technologies Transition to the New Doctoral Funding Model. European Social Fund Project No. ES32; • Ministry of Agriculture and Rural Support Service of the Republic of Latvia project No 19-00-A01612-000007 “Economically justified processing of whey for new food and feed”.