**Abbreviations**

624 Lactic Acid Bacteria – R & D for Food, Health and Livestock Purposes

Lactic acid production in LAB has both cell mass and growth dependent portions. Typically LAB require several nutrient components for their growth increasing the fermentation and down-stream processing costs. Down-stream processing is especially important in the production of lactic acid for PLA. As RP is the a major investment factor affecting costs, the minimization of medium and product purification costs should be accompanied by methods increasing cell mass concentration without excess growth. For this several different strategies have been applied so far mainly in academia (cell immobilization, cell-recycling and cell-retention). As history shows some of these could be applicable in industrial production as well, however pilot and demonstration plant studies and some risk-taking are

The main C/energy source spectrum available for LAB has been widened significantly. Reports of new possible substrates are frequently published, and the utilization of industrial side streams is a growing trend. Into this direction major successes have also been achieved with metabolic engineering providing strains for efficient production of lactic acid from

In an ideal fermentation process product inhibition should be minimized so that high RP would be achieved even at high lactic acid concentrations resulting in feasible average productivities. For this purpose both acclimatization and mutagenesis has been applied successfully. However, it has to be considered how far can we go in respect to fermentation pH and lactic acid concentration. There are already remarkable alternatives to LAB with naturally better properties in this sense. Some success has been achieved with in-situ

Conventional lactic acid production process with LAB is accompanied with the formation of large amounts of gypsum in the product recovery stage. Fermentation at lower pH diminishes this amount, but does not prevent its formation. Electrodialysis has been considered too expensive technique for the recovery of such cheap, bulk products as lactic acid. However, recent reports claim promising results with this technology. Forecasted figures for lactic acid market show up to one million tons per year. The growth would come mainly from the growth of PLA as a biodegradable polymer based on renewable raw materials. Economies of scale should decrease the production costs, but new technical

product recovery, but also these procedures lack experiences in any larger scale.

pentoses as well, which is to promote sustainable use of renewables.

approaches are also needed to reach these figures.

*University of Oulu, Faculty of Technology, Department of Process and* 

*Environmental Engineering, Bioprocess Engineering Laboratory, Oulu, Finland* 

**Author details** 

Corresponding Author

 \*

Sanna Taskila\* and Heikki Ojamo

**5. Conclusions** 

required.

η % - Efficiency, i.e. the ratio of YP/S to the maximum theoretical value

