An updated review on advancement in fermentative production strategies for biobutanol using Clostridium spp.

A significant concern of our fuel-dependent era is the unceasing exhaustion of petroleum fuel supplies. In parallel to this, environmental issues such as the greenhouse effect, change in global climate, and increasing global temperature must be addressed on a priority basis. Biobutanol, which has fuel characteristics comparable to gasoline, has attracted global attention as a viable green fuel alternative among the many biofuel alternatives. Renewable biomass could be used for the sustainable production of biobutanol by the acetone-butanol-ethanol (ABE) pathway. Non-extinguishable resources, such as algal and lignocellulosic biomass, and starch are some of the most commonly used feedstock for fermentative production of biobutanol, and each has its particular set of advantages. Clostridium, a gram-positive endospore-forming bacterium that can produce a range of compounds, along with n-butanol is traditionally known for its biobutanol production capabilities. Clostridium fermentation produces biobased n-butanol through ABE fermentation. However, low butanol titer, a lack of suitable feedstock, and product inhibition are the primary difficulties in biobutanol synthesis. Critical issues that are essential for sustainable production of biobutanol include (i) developing high butanol titer producing strains utilizing genetic and metabolic engineering approaches, (ii) renewable biomass that could be used for biobutanol production at a larger scale, and (iii) addressing the limits of traditional batch fermentation by integrated bioprocessing technologies with effective product recovery procedures that have increased the efficiency of biobutanol synthesis. Our paper reviews the current progress in all three aspects of butanol production and presents recent data on current practices in fermentative biobutanol production technology.

     

Water quality and bacteriology in an aquaculture facility equipped with a new aeration system

The HOBAS aeration system was tested to compare changes in environmental and bacteriological parameters in ponds growing Penaeus monodon during a single production cycle. The stocking density in the aerated pond was doubled to 12 post-larvae (PL) m^???2 in contrast to the non-aerated pond with 6 (PL) m^???2. Microbial abundance in the ponds ranged between 10^5???6 cells ml^???1. Among the physiological groups of bacteria enumerated, the heterotrophs dominated with an abundance of 10⁴ CFU ml^???1. Of the nitrogen and sulfur cycle bacteria, the nitrifiers flourished in the aerated pond and could maintain ammonia-N concentration within permissible levels. Bacterial activity also maintained sulfide concentrations at <?0.03 mg l^???1. Non-aerated conditions promoted denitrification maintaining nitrate concentration between 0.32 and 0.98 μM NO₃ ^???-N l^???1. However, a marked increase in ammonium content was observed in the non-aerated pond at the end of the culture period. Thus in high-density ponds, the aerators served to stimulate bacterial growth and activity which consequently maintained the quality of the water to match that of low-density ponds. Accordingly, these aerators could be effectively used to sustain higher yields. The effluent from the aerated pond is less likely to alter the redox balance of the receiving waters.     

Effects of carbaryl on the aminotransferases in the mid gut of blister beetle,Mylabris pustulata (Thunb)

The activity levels of aminotransferases such as alanine aminotransferases (AlAT), aspartate aminotransferases (AAT), isoleucine aminotranferases (IlAT), leucine aminotransferases (LAT), valine aminotrasferases (VAT) were measured in the mid gut of the blister beetle; Mylabris pustulata (Thunb) exposed to sublethal doses of carbaryl. The insecticide markedly inhibited the activity levels of all aminotransferases exposed for either short or prolonged treatments. The beetles regained normal enzymic activity after withdrawal from the treatment. It is possible that chronic exposures of beetles to carbaryl may induce impairment in protein synthesis in the mid gut of the beetle.     

Development of Water-Borne Green Polymer Used as a Potential Nano Drug Vehicle and its In Vitro Release Studies

This paper describes an ecofriendly development of a nanodrug delivery vehicle from seed oil. The entire synthesis, starting from the ZnO nanoparticle to the polymeric vehicle is purely microwave assisted with minimal usage of organic solvents. Multifunctional features like enhanced UV absorbance, antimicrobial properties and appreciable in vitro release can be attributed to the nanoparticle loaded polymeric vehicle. Characterization of the synthesized species was done through FT-IR, ¹HNMR, SEM and XRD. The physical characterizations were carried out using conventional laboratory techniques.     

Effects of UV-light on biochemical composition of silk gland of silkworm,Bombyx mori L. fed an artificial diet

The effects of UV-light on biochemical parameters of posterior silk gland of mulberry silkworm, Bombyx mori L. were investigated in two popular bivoltine hybrids, Jufang (Chinese) × Chenxin (Japanese) and Chenxin × Jufang fed an artificial diet. Larvae of the first day of fifth instar were used for the present investigation. The larvae were irradiated with 20 W of UV-light at the intensity of 40 cm above the larvae for one of three exposure times (30, 60 or 120 min) just before feeding. UV treatment produced no significant effects at 30 min. However, at 60 or 120 min there was a significant decrease in silk gland weight and the levels of total protein, free amino acids, RNA and carbohydrates. UV-light thus affects the biosynthetic activities of silk glands.