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Effective lactic acid (LA) production from lignocellulosic biomass materials is challenged by several limitations related to pentose sugar utilization, inhibitory compounds, and/or fermentation conditions. In this study, a newly isolated Bacillus coagulans strain Azu-10 was obtained and showed homofermentative LA production from xylose with optimal fermentation conditions at 50 °C and pH 7.0. Growth of strain Azu-10 and LA-fermentation efficiency were evaluated in the presence of various lignocellulose-derived inhibitors (furans, carboxylic acids, and phenols) at different concentrations. Furanic lignocellulosic-derived inhibitors were completely detoxified. The strain has exhibited high biomass, complete xylose consumption, and high LA production in the presence of 1.0‒4.0 g/L furfural and 1.0‒5.0 g/L of hydroxymethyl furfural, separately. Moreover, strain Azu-10 exhibited high LA production in the presence of 5.0–15.0 g/L acetic acid, 5.0 g/L of formic acid, and up to 7.0 g/L of levulinic acid, separately. Besides, for phenolic compounds, p-coumaric acid was most toxic at 1.0 g/L, while syringaldehyde or p-hydroxybenzaldehyde, and vanillin at 1.0 g/L did not inhibit LA fermentation. The present study provides an interesting potential candidate for the thermophilic LA fermentation from lignocellulose-derived substrates at the industrial biorefinery level.

The present study aimed to isolate and evaluate the potentiality of some probiotic lactic acid bacteria from infants stool to degrade and reduce cholesterol level in fermentation medium. Out of 50 lactic acid bacterial isolates recovered from healthy infants (3 to 18 months old) stool, two bacterial isolates W7 and Y1 showed highest cholesterol reduction percentage (68.38 and 71.6%, respectively). The cholesterol reduction potentiality by the two isolates W7 and Y1 were optimized to 94 and 98%, respectively, by studying the different cultural conditions; inoculum size, inoculum age, pH, incubation temperature, incubation period and cholesterol concentration. The gas chromatography analysis of the fermentation extract revealed that the resulted end product of cholesterol was 5a-cholestane-3a,25-diol (C27H48O2) of molecular weight 404. The selected bacterial isolate Y1 was identified phenotypically and genotypically as Enterococcus faecium and deposited in GenBank under the accession number KY788356. Key words: Cholesterol, Enterococcus, optimization, probiotic, gas chromatography.

Different fermentation strategies were investigated for improving lactic acid (LA) production by homofermentative LA-producing strain, Enterococcus hirae ds10. Batch mode with initial sugar molasses of 69.53 g/L achieved LA production of 36.79 g/L with a yield of 0.91 g/g and productivity of 1.02 g/L/h; however, 52% of sugar molasses was only consumed. Otherwise, in batch mode with high cell density (HCD), strain ds10 consumed more substrate achieving LA production at 49.49 g/L at yield (0.91 g/g) and low LA productivity (0.41 g/L/h). Subsequently, one-pulse and multi-pulse fed-batch strategies with/without HCD were provided better sugar utilization and higher LA production but low LA productivity was obtained. Interestingly, the repeated batch fermentation was conducted for 16 runs and achieved the highest LA of 61.76 g/L after 30 h at a higher initial sugar concentration of 85.87 g/L with an improvement of LA productivity at 2.06 g/L/h and yield at 0. 97 g/g.

The present work was planned to investigate the effect of different Lactobacillus acidophilusfiltrate levels on microbial and biochemical quality criteria of imported basa fish (Pangasius bocourti) fillets and heavy metals concentrations i.e. lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn) and iron (Fe). Fish fillets were immersed in cold distilled water containing (vv) 1%, 1.5% and 2% metabolites for 2 min. Each treatment was packed in polyethylene bags, put in foam dishes and all treatments were stored at -18°C for 30 days. Results showed that frozen contained low residue levels of cadmium (Cd 0.06), copper (Cu 0.42), zinc (Zn 3.0) and iron (Fe 4.98) but lead not detected. Also, basa fillets contained (on wet weight basis) high moisture (81.76 %) and low protein (11.24%), high lipid (4.99%) and ash (1.88%) contents. During frozen storage, Lb. acidophilusfiltrate levels decreased total plate count (TPC), psychrophilic, proteolytic and lipolytic bacteria in all treatments compared to control samples. Besides, the highest reduction rate in total volatile bases nitrogen (TVB) ranged 27.50–38.70 % in treatment 1% metabolites extract than other ones in particularly control samples under the same conditions. In case of trimethylamin (TMA), it was 29.73% in treatment 2% at first day and 33.33% in treatment 1.5% after 15 days storage. The high reduction rate in thiobarbituric acid (TBA) was 28.42% in treatment 2% at first day while it was 29.30% in treatment 1.5% after 15 days storage. In conclusion, the concentrations of Pb, Cd, Cu, Zn and Fe were lower than the maximum permissible limit and hence safe for human consumption. Bio-preserved techniques of fish fillets using Lb. acidophilus are controlled the change rate of bacterial and chemical quality aspects.

This study was designed to examine the antifungal activity of Lactobacillus Plantarum DSMZ 20191 on a variety of molds which normally contaminated the fish diet and my cause it`s deterioration and also affect it's shelf life. We used different concentration of the antifungal metabolites (1,2,3,4 and 5 ml/100g of the fish diets) to demonstrate it`s role in inhibition of fungal growth during storage of fish diets. According to our study Lb. plantarum DSMZ 20191exhibit high activity against Aspergillus sp. which contaminated animal fish diet especially at concentration of 5%, while in plant diet the antifungal activity against Aspergillus sp., Fusarium sp. and Penicillum sp.was lower. Finally the activity against Aspergillus sp. and Fusarium sp.in mixed fish diet was moderate.In conclusion LAB can be used in biopreservation due to their antifungal activity against a variety of molds which contaminate different food and feed and can cause serious deterioration and this can eliminate the use of chemical preservatives.