Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, A cartia tonsa:a laboratory study

The ef fects of salinity on the copepod, A cartia tonsa in terms of daily egg production rate(EPR), hatching success, fecal pellet production rate(FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods(seven consecutive days). Results show EPR was aff ected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females(long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages(56.7% and 52.2%, respectively) were signifi cantly observed at two salinities of 13 and 20 compared to that at 35(25%). Total longevity of females was not af fected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa.

Analysis of Metabolic Products by Response Surface Methodology for Production of Human-like Collagen II

Recombinant Escherichia coli BL21 is used to produce human-like collagen. The key constituents of media are optimized using response surface methodology (RSM). Before thermal induction, the highest biomass production and the lowest production of some hazardous by-products, especially acetic acid, were obtained in the media containing 0.085 mol·L-1 glucose and 0.019 mol·L-1 nitrogen (carbon-nitrogen ratio, 4.47:1). After thermal induction, when the concentrations of glucose and nitrogen in the media were 0.065 mol·L-1 and 0.017 mol·L-1 , respectively (carbon-nitrogen ratio, 3.82:1), the productivity of human-like collagen per cell was the highest while that of acetic acid was the lowest. The extended analysis showed that the production of lactic acid and propionic acid increased while that of some intermediate acids of the tricarboxylic acid cycle decreased if the dose of glucose increased.

Optimization of Fermentation Process for Human-like Collagen Production of Recombinant Escherichia coli Using Response Surface Methodology

In order to improve the production of human-like collagen III(HLC III)by fed-batch culture of recombinant Escherichia coli BL21,the Plackett-Burman and Box-Behnken design were applied to optimize the fermentation process parameters.Three variables(induction time,inoculum age and pH),which have significant effects on HLC III production,were selected from eight variables by Plackett-Burman design.With the regression coefficient analysis in the Box-Behnken design,a relationship between HLC III production and three significant factors was obtained,and the optimum levels of the three variables were as follows:induction time 3.2h,inoculum age 12.6 h and pH 6.7.The 3D response surface plots and 2D contour plots created by the Box-Behnken design showed that the interaction between induction time and pH and that between innoculum age and pH were significant.An average 9.68 g·L1HLC III production was attained in the validation experiment under optimized condition,which was 80%higher than the yield of 5.36 g·L1before optimization.

Optimum Fish for Fish Glue Processing for Fish Skin Value Added and the Glue Character

Fish glue is the collagen from scale skin and bone of fish. It is known for value added product from fish processing and the adhesive agent for wood paper book binding etc. This work was aimed with the method to produce fish glue from fish skin through representing optimum fish type and its glue character by study on standard method for fish glue processing （using Oreochromis niloticus skin as the model）, optimum fish type and characterization of the glue from optimum fish skin. Soaking fish skin in 0.1 N NaOH for 6 h and changed it every 3 h for pretreatment before acid extraction with 0.5 M acetic acid was the optimum condition for the standard processing. Among 20 types （O. niloticus, Oreochromis sp., Nemipterus sp., Psettodes erumei, Epiephelus malabaricus, Sphyraena obstsata, Channa striata, Xenentodon cancila, Barbonymus gonionotus, Liza vaigiensis, Anabas testudineus, Chanos chanos, Micronema bleekeri, Thunnus tonggol, Rastrelliger brachysom, Epinephelus lanceolatus, Lutjanus lineolatus, Pomadasys hasta, Selar crumenophthalmus and Sardaorentalis sp.）, Chanos chanos was an appropriate type for glue production. Fat, protein, carbohydrate, moisture, pH and viscosity of Chanos chanos glue were 0.32%, 4.23%, 83.8%, 11.56%, 3.35, 4,978.33-8,180 cp, respectively. The glue was collagen type I which was composed ofal （148 kDa） and a2 （129 kDa） chain and could bind paper, wood and foam sheet.