Sanna Taskila

The Current Status and Future Expectations in Industrial Production of Lactic Acid by Lactic Acid Bacteria

© 2013 Taskila and Ojamo, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Current Status and Future Expectations in Industrial Production of Lactic Acid by Lactic Acid Bacteria

Screening of white-rot fungi manganese peroxidases: a comparison between the specific activities of the enzyme from different native producers

In this study manganese peroxidase (MnP) enzymes from selected white-rot fungi were isolated and compared for potential future recombinant production. White-rot fungi were cultivated in small-scale in liquid media and a simplified process was established for the purification of extracellular enzymes.Five lignin degrading organisms were selected (Bjerkandera sp., Phanerochaete (P.) chrysosporium, Physisporinus (P.) rivulosus, Phlebia (P.) radiata and Phlebia sp. Nf b19) and studied for MnP production in small-scale. Extracellular MnP activity was followed and cultivations were harvested at proximity of the peak activity. The production of MnPs varied in different organisms but was clearly regulated by inducing liquid media components (Mn2+, veratryl alcohol and malonate). In total 8 different MnP isoforms were purified.Results of this study reinforce the conception that MnPs from distinct organisms differ substantially in their properties. Production of the extracellular enzyme in general did not reach a substantial level. This further suggests that these native producers are not suitable for industrial scale production of the enzyme. The highest specific activities were observed with MnPs from P. chrysosporium (200 U mg-1), Phlebia sp. Nf b19 (55 U mg-1) and P. rivulosus (89 U mg-1) and these MnPs are considered as the most potential candidates for further studies. The molecular weight of the purified MnPs was estimated to be between 45–50 kDa.

Modification of buffered peptone water for improved recovery of heat-injured Salmonella Typhimurium.

Rapid detection of Salmonella in foods is often limited by the high demand for the sensitivity of detection, poor physiological conditions of the target cells, and high concentration of background flora. In this study, the conditions of nonselective enrichment cultivation were modified in order to improve the quantitative detection of heat-injured Salmonella in minced meat. The effect of the modifications on the recovery was observed by means of RNA-based sandwich hybridization, which was adjusted for the quantification of Salmonella enterica 23S rRNA in crude cell extracts. The supplementation of buffered peptone water with the enzyme-controlled substrate delivery system EnBase-Flo and ferrioxamine E was shown to improve the recovery of cells in both single strain cultures and in the presence of minced meat. The presented results can be used for the development of more efficient enrichment cultivation media for faster detection of food borne Salmonella.

A discretized model for enzymatic hydrolysis of cellulose in a fed-batch process

In the enzymatic hydrolysis of cellulose, several phenomena have been proposed to cause a decrease in the reaction rate with increasing conversion. The importance of each phenomenon is difficult to distinguish from batch hydrolysis data. Thus, kinetic models for the enzymatic hydrolysis of cellulose often suffer from poor parameter identifiability. This work presents a model that is applicable to fed-batch hydrolysis by discretizing the substrate based on the feeding time. Different scenarios are tested to explain the observed decrease in reaction rate with increasing conversion, and comprehensive assessment of the parameter sensitivities is carried out. The proposed model performed well in the broad range of experimental conditions used in this study and when compared to literature data. Furthermore, the use of data from fed-batch experiments and discretization of the model substrate to populations was found to be very informative when assessing the importance of the rate-decreasing phenomena in the model.

Utilization of Industrial Microbe Side Streams for Biosorption of Heavy Metals from Wastewaters

The present report reviews the potential and applicability of industrial microbe side streams produced in Finnish bioprocess industries for biosorption of heavy metals from waste waters. Microbial side stream biomasses are formed worldwide in e.g. food, brewing, biofuel, pharmaceuticals, wood processing and enzyme manufacturing industries. Although these streams are typically used for low-valued animal feed or biogas production, they would also have potential for biosorbent materials to be used in in situ water treatment. Since major challenges have been recognized, especially regarding the availability of biomass, and to logistic and processing cost, biosorption is not the most economically attractive option for the use of these biomasses at the moment. However, in the future the situation may change due to new incentives or more cost-efficient biosorbent preparation technologies. This report will provide a knowledge basis for the consideration of biosorption applications for industrial microbe side streams.

Iron-loaded Sphagnum moss extract residue for phosphate removal

Sphagnum moss extract residue (SMER), obtained after pressurized hot water extraction, was modified with Fe(III) and investigated for phosphate sorption. Although moss extract contains value-added compounds, SMER is considered to be waste until suitable uses can be developed. The effect of modification conditions were investigated, i.e. different initial Fe(III) concentrations (0.024, 0.048 and 0.072 mol/L Fe3+) and modification pH values (5, 7 and 9). A modification pH of 5 and the highest initial Fe(III) concentration (0.072 mol/L Fe3+) resulted in the highest phosphate removal efficiency, and thus was selected for further study. The removal efficiency was found to decrease with increasing pH in the range of 3-9. Maximum removal efficiency (82%) for phosphate sorption was observed at pH 3 after 24 h contact time (dosage 2 g/L, initial concentration 15 mg P/L). With increased contact time, the phosphate removal efficiency improved and reached equilibrium within 48 h. The Elovich model was found to provide the best fit to the kinetic data. A capacity of 9-13 mg P/g was obtained with a 24-h contact time at pH 4. A good fit was achieved with the Redlich-Peterson equation. FTIR analysis confirmed that carboxylic acid groups were involved in the modification process. X-ray diffraction analyses showed that amorphous two-line ferrihydrite was precipitated onto SMER, which was supported by X-ray photoelectron spectroscopy analyses.

Concentration and Separation of Active Proteins from Potato Industry Waste Based on Low-Temperature Evaporation and Ethanol Precipitation

Purpose. Potato fruit juice, a residue of starch industry, contains up to 2.5% [w/w] of proteins that are potentially valuable raw-materials of food, cosmetic, and pharma industries. The recovery of protein from the potato fruit juice is limited by the lack of industrially feasible concentration and separation technologies. The present research thus aimed at development of such process for the separation of active protease inhibitors from potato fruit juice. Methods. Low temperature mechanical vapor recompression evaporation was applied for concentration of potato fruit juice followed by ethanol precipitation for recovery of active proteins. The effects of precipitation temperature and precipitative agents were investigated employing response surface modeling methodology. Results. Concentration of potato fruit juice by evaporation was successful without loss of trypsin inhibition activity. Precipitation using 6.5 M ethanol at low temperature (0–+4°C) was found suitable for the recovery of active protease inhibitors from the concentrate. Piloting at starch industry yielded 50% of total proteins, with a high quantity of active protease inhibitors and a minor inclusion of other proteins. Conclusion. Concentration by low-temperature evaporation, followed by ethanol precipitation of protease inhibitors at optimized temperature, is an attractive option for valorization of potato fruit juice.