Journal of Bioprocessing & Biotechniques

Aqueous two-phase extraction (ATPE), unique liquid-liquid extraction, involves a transfer of solute from one aqueous phase to another. ATPE includes polymer–polymer type and polymer–salt type systems for the recovery of proteins. The protein must be recovered in a highly purified form in order to improve its quality, decrease energy consumption, reduce waste and minimize costs. To acquire the high value and achieve good control over processes, the reliable, multi-component products are required especially those with the ability to investigate complex processing conditions. The current reviewing paper discusses the most recent progresses for the recovery of biomolecules by using the ATPE, covering the mechanism, which controls the phase formation and the behavior of solute partitioning in aqueous twophase systems (ATPS) processes. The review discusses also the increasing application for the recovery of high-value bioproducts, the recent development of alternative low cost ATPS and disadvantages attributed to ATPS.

Despite the tremendous success of cisplatin and other platinum-based anticancer drugs, severe toxicity and resistance to tumors limit their applications. It is believed that the coordination of the metal to DNA bases causes the ruptures of the cancer as well as normal cells. A search for anticancer drugs with different modes of action resulted in the synthesis of variety of novel compounds. Recently we synthesized a series of novel rhenium pentylcarbonato compounds (PC1-PC6). The rhenium atom in each compound is coordinated to a planar heterocyclic aromatic ligand, thereby forcing each compound to intercalate between the DNA bases. The UV absorption titrations of PC6 with DNA shows hypochromic effect with concomitant bathochromic shift of the charge transfer band at 290 nm. These results suggest that the compound PC6 binds to DNA through intercalation. It is likely that many of the other PC-series of compounds will behave in a similar manner. We have observed that the PC-series of compounds are strong cytotoxic agents against lymphosarcoma (average GI50 ≈ 2.3 ± .6 μM), PC-3 prostate (average GI50 ≈ 2.8 ± 0.6 μM) and myeloid leukemia (average GI50 ≈ 3.0 ± .6 μM) cancer cell lines. The average GI50 values of the PC-series of compounds are much less than the corresponding GI50 values of cisplatin. Also each of the PC-series of compounds exhibits less toxicity than cisplatin in the glomerular mesangial cells.

Bacterial cellulose has been found to be attractive for novel applications due to its material properties. An optimization of the medium used for the production of bacterial cellulose using Gluconacetobacter persimmonis was carried out. Plackett-Burman (PB) Design for screening of the medium constituents and a Central Composite Design (CCD) for optimization of significant factors were employed. Glucose, yeast extract and peptone were estimated as significant factors from PB design. Bacterial cellulose concentration of 1.72% (w/v) was obtained in the medium optimized using CCD method as compared to un-optimized medium that yielded 0.318% (w/v). Hence a 6 fold increase was observed after the optimization of medium was carried out. The combined effects of medium components and their optimum regions are reported in this paper.

The effects of two diurnally cyclic temperature ranges (20-40°C and 15-25°C) and four levels of hydraulic retention times (25, 20, 15, and 10 d) on the performance of anaerobic reactors operated on screened dairy manure were evaluated. The reactor temperature exhibited a lag relative to the chamber air temperature. For the 20-40°C temperature cycle, the average lags period at the maximum and minimum chamber temperatures 3.75 and 4.37 h, respectively. For the 15-25°C temperature cycle, the average lag periods at maximum and minimum chamber temperatures were 3.61 and 4.34 h, respectively. The effluent solids content were not adversely affected by the reactor diurnally cyclic temperature. The effluent total solids and methane content of the biogas diurnally cyclic patterns were out of phase with the diurnally cyclic pattern of the reactor temperature by about 12 hours under most operating conditions. The reductions in total solids and methane yield were all significantly affected by the diurnal temperature range and hydraulic retention time. Biogas production from a healthy digester operating under a diurnally cyclic temperature environment follow a sinusoidal pattern which can be described by a Fourier equation of the form. However, where the operating conditions are not favourable, the production followed a sinusoidal pattern which may be embedded in some harmonic and noise.

Co-culture processes present the opportunity to produce value-added products from economical raw materials, but there lacks a high-throughput fermentation monitoring technique to study the temporal physiology of fermentation organisms in co-culture processes. In this study, we applied shotgun proteomics to investigate a co-culture process of Saccharomyces cerevisiae and Scheffersomyces stipitis, and we monitored the fermentation until glucose depletion. Three time points were taken for proteomics analysis at 11.5 hour, 18.5 hour and 32 hour, representing transition into diauxic shift. Using label-free quantitation, we observed cellular dynamic within 20-hour time frame. We distinguished the proteome between two yeasts, and the most abundant proteins of S. stipitis and S. cerevisiae contained expected processes of glycolytic enzymes, histones, heat shock proteins, ribosomal proteins and F1F0-ATPase. After glucose depletion, we identified up-regulations of S. stipitis malate synthase and isocitrate lyase as key enzymes in glyoxylate cycle and gluconeogenesis. Increased expression of S. stipitis histone 2B was observed in diauxic shift, and histone acetylation was suggested by up-regulation of acetyl-CoA synthetase. Without the presence of xylose, we observed induction of NAD(P)H-dependent D-xylose reductase (Xyl1p) as early as 11.5-hour before glucose depletion. We also observed the expression of D-xylulose reductase after glucose depletion without xylose induction. Further study is needed to investigate the cause of derepression signals for xylose oxo-reductive pathway. Without cellulose induction, the up-regulation of S. stipitis endo-1,4-beta-glucanase suggested S. stipites’ strategy in diversifying carbon choices after glucose repression. This research demonstrated the application of shotgun proteomics in high-throughput monitoring of complex co-culture system and able to elucidate the temporal physiology of S. stipitis.

The adsorptive removal chromium, nickel, copper and cadmium by alginate beads containing a mixed consortium of Yeast, Pseudomonas aeruginosa, Bacillus subtilis and Escherichia coli in batch and fluidized bed column reactor was investigated. Under optimized conditions (pH 4.5; contact time 3hrs; initial metal concentration of 150mg/L) batch experiments showed that the immobilized mixed culture was successfully used for the removal of these metal ions in waste water. Fluidized bed studies were carried out in with an adsorbent dosage of 1g/L, a flow rate of 132 LPH, a bed height of length of the reactor. Efficiency of biosorption for copper, cadmium, chromium and nickel was found to be 84.62%, 67.17%, 49.25% and 61.02%. Desorption of the exhausted beads was found to be successful, however with a reduced biosorption capacity.

The biosorption characteristics of alkaline treated marine green algae (Ulva lactuca) have been studied for the removal of Pb(II), Zn(II) and Co(II) from aqueous solution, at room temperature. Batch experiments were performed to examine the effect of NaOH concentration used for treatment, initial heavy metals concentration and contact time, in comparison with untreated algae. The biosorption capacity of alkaline treated marine green algae increases with increasing of NaOH concentration, up to 0.6 mol L^-1, when an improvement of biosorption capacity with 11.75% for Pb(II), 60.64% for Zn(II) and 62.53% for Co(II) respectively, was obtained. The Langmuir model provides best correlation of equilibrium experimental data, and the pseudo-second order describes well the biosorption kinetics of considered heavy metals. The heavy metal ions could be easily desorbed from loaded biosorbent, and this may be reuse at least in three biosorption/desorption cycles.