Enzymatic hydrolysis has been widely applied for production of protein hydrolysate from shrimp waste and for purification of chitin. In the present study, shrimp (P. semisulcatus) head waste was hydrolysed, using a commercial proteolytic enzyme, Alcalase. In order to improve protein extraction efficiency, certain chemicals such as sodium sulphite and Triton x-100 were used along with the enzyme. When Alcalase (12 AU/kg) used alone, the yield of protein extraction was 45.1% and by using Triton x-100 (0.01 g/kg) together with Alcalase, the yield was decreased to 39%, whereas the presence of sodium sulphite (200 mmol/L) with the enzyme or with the enzyme and Triton x-100 increased the level of protein extraction to 62% and 65.1%, respectively. The resulting protein powder contained sufficient amounts of essential amino acids to be used in feed formulations. By precipitating proteins from the resulting protein extract at pH 3.1, the residual sulphite in protein powder was decreased by 97% and thus the powder can be considered suitable for animal and/or aquaculture feed formulations.

The temperature-induced, over-expression of the human growth hormone gene in a recombinant E. coli during high cell density cultivation is reported. Human growth hormone (hGH) production and stability were tested under different heat shock conditions. Cell densities were 25 and 60 g l(-1) in a pH-stat fed-batch mode in defined and complex medium, respectively, and the fermentation time was decreased from 41 to 32 h. hGH was produced at 2 g l(-1) in complex medium. By using glycerol as main carbon source in the complex medium with exponential feeding, cell density and hGH production were increased to 100 g l(-1) and 2.7 g l(-1), respectively.

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Genetically manipulated food barley, Hordeum vulgare L. var. valfajr, was compared to commercial-grade starch as carbon sources in groundnut and soybean based media for supporting growth, sporulation and delta-endotoxin production by Bacillus thuringiensis Berliner B. thuringiensis kurstaki HD-1 and a promising newly isolated B. thuringiensis strain (referred to as BTA) were used. MgCl 2 , CaCl 2 , and MnCl 2 were used as trace-elements. Culture media were compared in shaken flasks and then in 5 l Fermentors. Biomass, delta-endotoxin levels and the number of spores as colony forming units (CFU) were evaluated. For each of the two strains, biomass and delta-endotoxin synthesis were not significantly different in soybean-based media after substitution starch by barley flour. There were significant differences between the two strains with respect to biomass and toxin production. Evaluated costs of media preparation showed that food barley is an economical alternative to commercial-grade starch in the production of BTA bioinsecticide.

Endogenous bacterial strains possessing a high bisphenol A (BPA)-tolerance/degradation activity were isolated from different outlets of petrochemical wastewater in Iran using the enrichment cultivation approach.

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