مجید حیاتی آشتیانی

Tissue plasminogen activator is a recombinant protein for treatment. The main industrial production process of this tissue plasminogen activator mainly includes laboratory growth, fermentation, and separation. This study examines the equipment used in separation process, namely centrifuge, ultrafilter, microfilter, chromatography column, ER column, bottler, freeze dryer and mixing tanks, and the unit operations of this section. Retrofitting such as process debottlenecking (time debottlenecking of freeze dryer) and parallelization of the operations for each batch (1.6 kg product) was carried out and the minimum production time was reduced from 12 to less than 7 days and 23 hours for each batch. A storage tank was also installed to prevent the unit shutdown during the freeze-drying failure. The economic analysis shows the share of the direct costs including raw materials, utilities, etc. is 61.73% per batch and the share of indirect costs including lab charges, marketing, research and development, etc. is 38.27%. Arginine includes 97% of the total $247,000 of raw materials costs. Costs of investment, purchase, equipment installation and essentials needed are estimated to be $39,000,000. This cost is mainly for bottling and freeze-dryer systems.

Pinch Technology is one of the effective and practical methods for energy consumption economization. In this research, Pinch Technology has been used for energy consumption optimization in the isomerization unit. As a result, heat pumps have been used for energy consumption optimization in this unit in which the amount of energy consumption in heating and cooling utilities has decreased from 128.61 GJ/h and 143.9 GJ/h to 127.8 GJ/h and 152.0 GJ/h, respectively. This energy-saving leads to a decrease in the amount of energy consumption and an increase in the efficiency of the unit. Heat pumps have been additionally applied to study the heat exchangers with the highest amount of cross-pinchheat transfer. This study resulted in a significant decrease in the cross-pinch heat transfer, from 22.47 GJ/h to 19.90 GJ/h (11.3% decline).

When aflatoxin contaminated food is given to lactating animals, the metabolite of aflatoxin, called M, is secreted in milk. Since pasteurization, sterilization, and milk processing have little effect on the survival and reduction of AFM1 toxicity, this poison ultimately transports to various dairy products and endangers consumer health. Along with the negative effects of mycotoxins on health and livestock products, these compounds can to be effective in digestion, metabolism and ruminal microbial populations. In ruminants (especially lactating cows) fed with AFB1 contaminated feeds, health problems such as liver cancer, reduce immunity, reproductive disorders, malformation, decreased feed intake and milk production have also been reported. An increase in liver enzymes can be attributed to the signs of an abnormal body. In addition, previous studies aluminosilicate has been show to tightly bind aflatoxins in vitro. This significantly reduce mortality and morbidity in animals, decrease molecular biomarkers of aflatoxin exposure in humans and animals.

Two experiments were conducted to investigate the effect of aflatoxin B1 and aluminosilicate toxin adsorbents on the parameters of gas production contains gas production potential (b) and gas production rate (c), in vitro fermentation parameters includes pH, ammonia nitrogen concentration, volatile fatty acids and ruminal digestion. In the first experiment, the effects of different levels of AFB1, including 0, 300, 600 and 900 ng/ml, were investigated on the parameters of gas production, fermentation and digestion using batch culture method. In the second experiment the effectiveness of three aluminosilicate adsorbents on the AFB1 detoxification was investigated. MegaBond and MycoBond as native adsorbents and MilBond as a commercial adsorbent were used in 6% of DM. The gas produced was recorded at 2, 4, 6, 8, 12, 16, 24, 48, 72 and 96 h of the incubation. The data obtained were fitted to the non-linear equation to calculate parameters of gas production. Also, at the end of 24 h incubation, four bottles were transferred to refrigerator to stop fermentation. Then, pH, ammonia nitrogen concentration and volatile fatty acid (VFA) of batch culture medium was measured, as well as the dry matter digestibility.

Results of first experiment indicated that with increasing the AFB1 from 0.0 to 900 ng/ml, the gas production rate (c) decreased from 0.134 to 0.092 ml/h and the gas production potential (b) decreased from 160.7 to 131.3, but there was no significant difference between the treatments 0 and 300 ng/ml AFB1. In addition, the gas production lag phase increased significantly with increasing level of AFB1 (P<0.05). Addition of AFB1 to the batch culture did not affect its pH, but the dry matter digestibility significantly decreased (P<0.05) with increasing AFB1. Ammonia nitrogen concentration decreased significantly (P<0.05) with AFB1 addition, so that the lowest concentration of ammonia nitrogen was observed at 600 and 900 ng/ml AFB1 (15.2 and 15.3 mg/dL, respectively). In this experiment the total VFA concentration decreased significantly with AFB1 (P<0.05), but the molar ratio of acetate, propionate, butyrate, valerate and isovalerate was not affected (P>0.05). In the second addition of different aluminosilicate adsorbents significantly reduced the rate and potential of gas production. Likewise, dry matter digestibility and ammonia nitrogen concentration reduced significantly (P<0.05). Significant increase in pH of the culture medium by addition of aluminosilicate adsorbents can be attributed to the fact that aluminosilicate acts as a modifier of hydrogen ion in the environment due to the replacement of cations with hydrogen ion and prevents a significant decrease in rumen pH. Probably lowering the ammonia nitrogen concentration is due to the fact that the protozoan population is affected by aluminosilicate adsorbent and decreases; consequently, the population of the ruminal bacteria increases, which results in the removal of more ammonia nitrogen by microorganisms, and ultimately the concentration ammonia nitrogen decreases in the rumen.

The results of this study showed that AFB1 reduced gas production rate (c), the gas production potential (b), the concentration of ammonia and digestibility, but the pH is not affected in vitro. Also, none of the adsorbents was able to neutralize or reduce the negative effects of AFB1 on the parameters of gas production, fermentation and rumen digestion, which could be due to the absorption mechanism of aluminosilicate adsorbents for AFB1 absorption. The results of this study indicate that adsorbents cannot reduce the negative effects of AFB1 on digestion and rumen fermentation, therefore only proposed strategy is to prevent the contamination animal feed with mycotoxins.

This paper examines heavy metals removal from synthetics wastes by the use of natural and sulfuric acid-activated bentonite so that a cheap adsorbent can be attained for removing these metals from the wastes. Bentonite is a 2:1 layer aluminnisilicate whose dominant mineral is montmorillonite which is a nano-structure and nanoporous material. Montmorillonite affects all the properties of bentonite. In the next step, the effect of acid activation on the adsorption of both of lead (Pb) and thallium (Tl) is studied. In this research, after the mineralogical and chemical composition analyses by X-ray diffraction and fluorescence (XRD and XRF) methods, granulometric analysis is carried out on five samples namely, S2-RAW, S3-RAW, ES3-RAW, G1-RAW and GH1-RAW to remove the heavy metals such as Cr, Co, Cu, Fe, Pb, Tl, Ni, and Zn accompanying atomic absorption spectroscopy (AAS). Then, the effect of four factors including concentration, liquid to solid ratio (L/S), time, and activation temperature in acid activation process were studied. This process is done by a mineral acid, sulfuric acid, to promote the adsorbability of lead and thallium in both natural and activated types of ES3-RAW and GH1-RAW. In all case, due to the presence of dominant mineral of nano-montmorillonite and its unique structure, montmorillonite has a higher adsorbability in comparison with that of the other clay minerals.