[Behavioral and physiological responses to hypoxia stress in male and female Macrobrachium rosenbergii]. / 雌雄罗氏沼虾应对低氧胁迫的行为生理响应.

To explore the physiological and behavioral responses of male and female Macrobrachium rosenbergii under hypoxia stress, an experiment with three dissolved oxygen (DO) levels (6.46, 4.48 and 3.27 mg·L-1, 6.46 mg·L-1 as control) was conducted. The enzyme activities of energy metabolism in hepatopancreas and muscles of male and female M. rosenbergii were measured after six days of hypoxia stress. The results showed that the enzyme activities of aerobic metabolism in muscles and swimming abilities were significantly decreased as DO decreased from 6.46 mg·L-1 to 4.48 mg·L-1, with the decreases being less in males than females. There was no significant difference in enzyme activities of anaerobic metabolism. When DO was further decreased to 3.27 mg·L-1, the enzyme activities of aerobic metabolism and anaerobic metabolism in muscles significantly decreased. The activity of lactate dehydrogenase (LDH) in anaerobic metabolism of hepatopancreas and tail-flipping speeds significantly decreased in males and females, with less decrease in females than that in males for LDH activity of hepatopancreas. The swimming ability was positively correlated with the enzyme activities of aerobic metabolism in pleopods muscles. There was significant correlation between tail-flipping abilities and enzyme activities of anaerobic metabolism. M. rosenbergii could reduce its reliance on energy metabolism during hypoxia stress, but with negative consequences on locomotor abilities. The muscles were preferentially powered to meet energy requirements of locomotion in males, while females gave priority to energy supply for hepatopancreas under insufficient oxygen conditions.

Vacuum-assisted black liquor-recycling enhances the sugar yield of sugarcane bagasse and decreases water and alkali consumption.

Black liquor (BL) remains a critical problem during alkaline pretreatment. To solve this issue, a novel pretreatment strategy termed vacuum-assisted black liquor-recycling pretreatment, was established to pretreat sugarcane bagasse (SCB). Firstly, SCB was pretreated with 2% NaOH at 121 °C for 1 h under vacuum conditions. The produced BL was used for subsequent pretreatments after pH recovery with NaOH. The pretreated SCBs were subject to enzymatic hydrolysis and separate hydrolyzation and fermentation (SHF) without washing to neutral pH. BL was recycled on seven occasions. The results indicated that glucose yields did not significantly differ between pretreatment with NaOH and recovered BL. The enzymatic hydrolysis and the fermentation resulted in maximum 0.35 g/g of glucose yield and 116.5 g/kg of ethanol yield respectively. Compared with conventional pretreatment with NaOH, the VABLR method showed high conversion rates of cellulose into monosaccharaides, whilst preserving ~20% and ~46% of alkali and water usage, respectively.