Detection of extracellular bound proteinase in EPS-producing lactic acid bacteria cultures on skim milk agar

AIMS: Skim milk agar was developed to investigate extracellular cell-bound proteinase in yogurt cultures, Streptococcus thermophilus and Lactobacillus bulgaricus. METHODS AND RESULTS: The Lact. bulgaricus cultures produced more extracellular cell-bound proteinase than did Strep. thermophilus cultures. Strong positive correlations between the size of the exopolysaccharide (EPS) layer and extracellular cell-bound proteinase were found for both Streptococcus and Lactobacillus cultures. CONCLUSION: Strong positive linear relationships existed between the EPS size and colony size and the diameter of clear zone and colony size for Streptococcus cultures, whereas weak positive linear relationships were observed for Lactobacillus cultures. SIGNIFICANCE AND IMPACT OF THE STUDY: These data are useful to validate the relationship between extracellular proteinase and the EPS size of LAB. Also, a convenient medium to detect the presence of extracellular cell-bound proteinase of LAB is valuable for dairy industries.     

Correction to: Butanol and butyric acid production from Saccharina japonica by Clostridium acetobutylicum and Clostridium tyrobutyricum with adaptive evolution

Bioprocess and Biosystems Engineering - Unfortunately, the author name was wrongly published as Pailin Sukwang.instead of Pailin Sukwong.     

Purification of l-(+)-lactic acid from pre-treated fermentation broth using vapor permeation-assisted esterification

The vapor permeation-assisted esterification of l-(+)-lactic acid and ethanol was investigated using a zeolite membrane. Pervaporation and vapor permeation were initially investigated for dehydration performances, and the latter showed much better results. The molecular sieve property of the membrane resulted in a high separation factor of over 1000 for all conditions. The maximum flux was 10.24 kg/(m² h) at a feed temperature of 145 °C, a water feed concentration of 10 wt%, and a feed pressure of 4.0 bars, respectively. For vapor permeation-assisted esterification using synthetic solutions, the productivity and ethyl lactate yield strongly depended on the dehydration rate. Realistic purifications were performed with fermentation broths of Pediococcus pentosaceus as the lactic acid producer. Experimental results revealed that most of the lactic acid was converted into ethyl lactate at the final stage of the reaction. After distillation and hydrolysis, high purity l-(+)-lactic acid was obtained with more than 95% recovery yields.     

Butanol and butyric acid production from Saccharina japonica by Clostridium acetobutylicum and Clostridium tyrobutyricum with adaptive evolution

Optimal conditions of hyper thermal (HT) acid hydrolysis of the Saccharina japonica was determined to a seaweed slurry content of 12% (w/v) and 144 mM H₂SO₄ at 160 °C for 10 min. Enzymatic saccharification was carried out at 50 °C and 150 rpm for 48 h using the three enzymes at concentrations of 16 U/mL. Celluclast 1.5 L showed the lowest half-velocity constant (K_m) of 0.168 g/L, indicating a higher affinity for S. japonica hydrolysate. Pretreatment yielded a maximum monosaccharide concentration of 36.2 g/L and 45.7% conversion from total fermentable monosaccharides of 79.2 g/L with 120 g dry weight/L S. japonica slurry. High cell densities of Clostridium acetobutylicum and Clostridium tyrobutyricum were obtained using the retarding agents KH₂PO₄ (50 mM) and NaHCO₃ (200 mM). Adaptive evolution facilitated the efficient use of mixed monosaccharides. Therefore, adaptive evolution and retarding agents can enhance the overall butanol and butyric acid yields from S. japonica.

     

Improved fermentation performance to produce bioethanol from Gelidium amansii using Pichia stipitis adapted to galactose

Bioprocess and Biosystems Engineering - This study employed a statistical method to obtain optimal hyper thermal acid hydrolysis conditions using Gelidium amansii (red seaweed) as a source of...     

Enhancement of bioethanol production from Gracilaria verrucosa by Saccharomyces cerevisiae through the overexpression of SNR84 and PGM2

Bioprocess and Biosystems Engineering - A total monosaccharide concentration of 47.0 g/L from 12% (w/v) Gracilaria verrucosa was obtained by hyper thermal acid hydrolysis with...     

Roles of kisspeptin in IVF/ICSI-treated infertile women and in human granulosa cells

Kisspeptin, a crucial central regulator of reproduction, has been used as a trigger in in vitro fertilization (IVF) treatment. This study aimed to investigate the roles of kisspeptin in IVF treatment in infertile females (n = 30); and in steroidogenesis in human granulosa-like tumor cell line (KGN). In the human study, blood was collected at three time points including (1) the beginning of gonadotropin stimulation (Phase I), (2) around eight days after gonadotropin stimulation (Phase II), and (3) on the day of ovum pick-up (Phase III). Follicular fluid (FF) was collected at Phase III. Serum human chorionic gonadotropin (hCG) was measured 15 days after embryo transfer and fetal heart beats were determined around 42 days of menstrual cycle to classify the subjects into successful and unsuccessful groups. FF kisspeptin levels were higher in successful compared with unsuccessful subjects (P < 0.01). Kisspeptin levels were significantly higher in FF than in serum in successful subjects (P < 0.05) but were comparable in unsuccessful subjects. Serum kisspeptin was comparable among three phases in the successful group but its levels in Phase III were significantly lower compared with Phase I in the unsuccessful group (P < 0.01). Serum kisspeptin in Phase II/III had positive correlations with serum E2 in Phases II and III and the outcomes of IVF/intracytoplasmic sperm injection (ICSI) treatment including serum hCG levels. For the cell experiment (n = 3), kisspeptin treatment in the presence of FSH together with IGF-1 enhanced CYP19A1 (aromatase) mRNA expression compared with control. FSH alone increased aromatase concentrations in the supernatant compared with control and kisspeptin at the dose of 10^-2 mmol/L with FSH enhanced aromatase concentrations in the supernatant compared with FSH alone (P < 0.001 all). In conclusion, kisspeptin enhanced aromatase expression and secretion and was associated with positive outcomes of IVF/ICSI treatment. Further studies regarding supplementation of kisspeptin could reveal its beneficial effects on IVF/ICSI treatment.