Application of Pectin Crude Extract from Krung Kha Mao Leaves （Cissampelos pareira L.） for Immobilization of Lactobacillus casei subsp, rhamnosus TISTR 108 and Lactobacillus delbrueckii subsp, bulgaricus TISTR 1339 on Lactic Acid Production

The research was first to perform the utilization of novel and cheap pectin crude extract from Krung Kha Mao leaves （Cissampelos pareira L.） to immobilize cells of Lactobacillus casei subsp, rhamnosus TISTR 108 and Lactobacillus delbrueckii subsp, bulgaricus TISTR 1339 for lactic acid production, the optimum condition of immobilized cells was produced significantly at 5% of probability, that the highest lactic acid has been 38.50 and 33.66 g/L in steady state of whey medium for 96 and 108 h, respectively. Both strains were immobilized by 4% （w/w） of pectin crude extract from Krung Kha Mao （KKM pectin） leaves, 1.52 mm inner diameters of silicone tube and 5% （v/v） inoculum for immobilization. Efficiency of lactic acid production was compared by immobilized cells ofL. casei subsp, rhamnosus TISTR 108 when KKM pectin, commercial citrus pectin, commercial apple pectin and sodium alginate were used as supporting materials to produce lactic acid 38.50, 38.76, 30.43 and 34.56 g/L, respectively, the productivity of lactic acid has been 0.40, 0.40, 0.36 and 0.36 g/L h, respectively.

Continuous Lactic Acid Production from Longan Juice by Lactobacillus casei subsp, rhamnosus TISTR 108

This research focused using novel substrate, longan Lactobacillus casei subsp, rhamnosus TISTR 108. The optimum juice as carbon source for continuous lactic acid production by medium for lactic acid production was pure longan juice with 120 g/L sugar concentration and among the different nitrogen sources were added to the longan juice （yeast extract, tryptic soy, urea, （NH4）2SO4 and NaNO3）, yeast extract had the most efficiency. Yeast extract （10 g/L） without adding minerals to longan juice could produced the maximum lactic acid concentration of 38.91 ± 0.190 g/L in 60 h and the yield of 0.460± 0.122 g/g with the productivity of 0.649± 0.002 g/Lh in 2 liters flask. Batch fermentation was conducted in 2 liters fermentor and 41.38± 0.030 g/L lactic acid was produced in 48 h with the yield of 0.398 ± 0.215 g/g and the productivity was 0.862 ± 0.001 g/L h. The continuous fermentation using 2 liters fermentor as a high productivity for lactic acid （1.091 ± 0.001 g/L h） was achieved at dilution rate （D） of 0.0685 h-1.

Improvement of Propionic Acid Production for Antifungal Activity from Whey by Calcium Alginate Immobilization of Propionibacterium acidipropionici TISTR 442

The improvement of propionic acid production for antifungal activity, as fermenting by calcium alginate immobilized cells of Propionibacterium acidipropionici TISTR 442 was investigated by using whey as substrate. Optimal condition for immobilization was performed by adjusting tube distance to CaCI2 solution to be 4-6 cm and 7 mL/min flow rate of alginate gel. The production of propionic acid by immobilized cells in a 2 L fermentor using 1% CaCO3 and 5 N KOH to control the pH at 6.5 gave maximum propionic acid and they had consistent potential to recycle 2 rounds of fermentation and produced the total of 29.24 g/L propionic acid （15.85 ± 0.25 g/L and 13.39 ± 0.25 g/L propionic acid from Batch 1 and Batch 2 fermentation, respectively）. Compared to free-cell fermentation, propionic acid productivity increased 20% （0.083 g/h vs. 0.070 g/h） and fermentation time reduced 11% （192 h vs. 216 h） in 2 L fermentor with 40 g/L initial total sugar from whey. The fermented propionic acid as well as the commercial propionic acid from chemical process was able to inhibit the growth of the fungal tested.

Mode of Action and Cytotoxicity of Bioactive Compounds Produced by Streptomyces sp. KB1

Rapid emergence of methicillin-resistant Staphylococcus aureus (MRSA) has led to search of a novel bioactive compounds from natural resources. This study was aimed to determine the mode of action of bioactive compounds produced by Streptomyces sp. KB1 TISTR 2304 against MRSA, including cytotoxicity against mature brine shrimp. The mode of action and cytotoxicity of bioactive compounds were performed by observing the tested MRSA cells with a scanning electron microscope and evaluated by the brine shrimp lethality bioassay, respectively. The results indicated that bioactive compounds had the mode of action at the cell wall and also showed the moderate cytotoxic activity. This study concluded that the bioactive compounds produced from strain KB1 can be used as a model for novel anti-MRSA drug development.