Repurposing of waste PET by microbial biotransformation to functionalized materials for additive manufacturing.

Plastic waste is an outstanding environmental thread. Poly(ethylene terephthalate) (PET) is one of the most abundantly produced single-use plastics worldwide, but its recycling rates are low. In parallel, additive manufacturing is a rapidly evolving technology with wide-ranging applications. Thus, there is a need for a broad spectrum of polymers to meet the demands of this growing industry and address post-use waste materials. This perspective article highlights the potential of designing microbial cell factories to upcycle PET into functionalized chemical building blocks for additive manufacturing. We present the leveraging of PET hydrolyzing enzymes and rewiring the bacterial C2 and aromatic catabolic pathways to obtain high-value chemicals and polymers. Since PET mechanical recycling back to original materials is cost-prohibitive, the biochemical technology is a viable alternative to upcycle PET into novel 3D printing materials, such as replacements for acrylonitrile butadiene styrene. The presented hybrid chemo-bio approaches potentially enable the manufacturing of environmentally friendly degradable or higher-value high-performance polymers and composites and their reuse for a circular economy. ONE-SENTENCE SUMMARY: Biotransformation of waste PET to high-value platform chemicals for additive manufacturing.

The chloramine stress induces the production of chloramine decaying proteins by microbes in biomass (biofilm).

In this paper, for the first time, we show in chloraminated systems, the chloramine decaying proteins (CDP) play an important role in bulk water and biomass (biofilm) in resisting disinfectant. Extracellular polymeric substances in biofilm/biomass are known to protect microbes from disinfectants and toxic materials, but the exact mechanism(s) is/are not known. Starting with the seed from a nitrifying chloraminated reactor, two 5 L reactors were fed intermittently with either chloramine or ammonia containing nutrient solution. The degree of nitrification increased with time in both reactors despite an increase in soluble CDP in the chloraminated reactor, while soluble CDP decreased in the ammoniated one. The suspended biomass collected after eight months of operation from chloraminated reactor contained CDP and responded to short-term chloramine stress (1.5 h with initial 1.5 mg-Cl2·L-1) by the additional production of soluble CDP. The suspended biomass from ammoniated reactor neither contained CDP nor produced soluble CDP as a stress response. The production, release and accumulation of CDP in biomass (biofilm) could be one of several mechanisms microbes use to defend against disinfectants (stress). The new understanding will pave the way for better disinfection management and better design of experiments.

Effects of feed water NOM variation on chloramine demand from chloramine-decaying soluble microbial products during rechloramination.

Earlier, we reported on soluble microbial products-mediated chloramine decay in nitrifying waters. However, we neither separated the agent(s) nor identified the factors that enhanced the production of chloramine-decaying soluble microbial products (cSMPs). Experiments were conducted by feeding reactor sets (each consisting of five reactors connected in series) with treated water (3-8 mg-DOC.L-1) obtained from a water treatment plant. The reactors simulated various nitrifying conditions that are experienced in a chloraminated system. In unfiltered samples obtained from nitrified reactors, about 89-93% of the dosed chloramine decayed within 40 h. The cSMP-mediated decay accounted for 21-39% of all chloramine decay in the samples from 0 to 5 mg-C.L-1 fed reactors and 15% in the samples from 7 to 8 mg-C.L-1 fed reactors. Microbial processes (mediated by nitrifiers and/or heterotrophs) and biomass-associated microbial products (BMPs) in insoluble form accounted for 13-21% for the reactors fed with 0-5 mg-C.L-1 and 34% for those fed with 7-8 mg-C.L-1. The cSMPs were separable with a 30 kDa cut-off membrane but not with 50 or 100 kDa membranes, i.e., they were above 30 kDa but below 50 kDa in size, and were confirmed to be a protein(s). The protein(s) accelerated chloramine decay by accelerating chloramine auto-decomposition and nitrite oxidation. As opposed to the traditional belief, unknown factors accounted for approximately 34-53% in commonly encountered re-chloraminated nitrifying waters (2-5 mg-DOC.L-1). Understanding the identity and role of these factors - such as cSMPs, BMPs, heterotrophs - will lead to a better control of chloramine.

Clinical Utility of Blood Cell Histogram Interpretation.

An automated haematology analyser provides blood cell histograms by plotting the sizes of different blood cells on X-axis and their relative number on Y-axis. Histogram interpretation needs careful analysis of Red Blood Cell (RBC), White Blood Cell (WBC) and platelet distribution curves. Histogram analysis is often a neglected part of the automated haemogram which if interpreted well, has significant potential to provide diagnostically relevant information even before higher level investigations are ordered.

Her-2/neu overexpression due to polysomy 17 in breast cancer: molecular testing to guide therapeutic options.

BACKGROUND: Fluorescent in situ hybridization (FISH) equivocal results for Her-2/neu still pose a diagnostic dilemma in oncology practice. In this study, we evaluate if Her-2/neu mRNA expression is an alternative to FISH for detecting Her-2/neu positivity. PATIENTS AND METHODS: Archival paraffin blocks of 54 breast cancer patients were analyzed for Her-2/neu status using immunohistochemistry (IHC), FISH, and Her-2/neu gene expression using mRNA. RESULTS: There was a 100% positive agreement and 64.7% negative agreement of Her-2/neu mRNA expression with respect to the reference standard (FISH), with the kappa value for agreement being 0.36. mRNA levels correlated positively and strongly with FISH ratio and IHC positivity. For Her-2/neu mRNA expression, Her-2/neu copy number was a significant predictor indicating that mRNA expression is independent of polysomy status. CONCLUSIONS: Her-2/neu mRNA expression may help tide over ambiguity posed by polysomy and FISH equivocal samples.

Toxicity studies of detoxified Jatropha meal (Jatropha curcas) in rats.

Jatropha curcas, a tropical plant introduced in many Asian and African countries is presently used as a source of biodiesel. The cake after oil extraction is rich in protein and is a potential source of livestock feed. In view of the high toxic nature of whole as well as dehulled seed meal due to the presence of toxic phorbol esters and lectin, the meal was subjected to alkali and heat treatments to deactivate the phorbol ester as well as lectin content. After treatment, the phorbol ester content was reduced up to 89% in whole and dehulled seed meal. Toxicity studies were conducted on male growing rats by feeding treated as well as untreated meal through dietary source. All rats irrespective of treatment had reduced appetite and diet intake was low accompanied by diarrhoea. The rats also exhibited reduced motor activity. The rats fed with treated meals exhibited delayed mortality compared to untreated meal fed rats (p0.02). There were significant changes both in terms of food intake and gain in body weight. Gross examination of vital organs indicated atrophy compared to control casein fed rats. However, histopathological examination of various vital organs did not reveal any treatment related microscopic changes suggesting that the mortality of rats occurred due to lack of food intake, diarrhoea and emaciation. Further studies are in progress for complete detoxification of J. curcas meal for use in livestock feed.

Quality characterization of pasta enriched with mustard protein isolate.

Mustard protein isolate (MPI) prepared by steam injection heating for removal of antinutritional factors was used at different levels, including 0%, 2.5%, 5%, and 10%, for supplementation of pasta products. The effects of supplementation levels on rheological properties of pasta dough and chemical composition, and cooking, nutritional, and color characteristics of dried samples were evaluated. The results showed that as the supplementation level increased, the dough development time (DDT) increased from 3.5 min in the control to 13.8 min in 10% supplementation level. Maximum consistency (MC) increased from 351 farinograph units (FU) in the control to 371 and 386 FU in 2.5% and 5% supplementation levels, respectively, but decreased to 346 FU in 10% supplementation level. Mixing tolerance index (MTI) decreased as the supplementation increased. The most pronounced effect of enrichment on chemical composition was the increase in protein content; the increase was around 4.5% with supplementation of each 5% MPI in pasta formulation. Study of cooking characteristics of enriched pasta samples showed that cooked weight, cooking loss, protein loss, and stickiness decreased and firmness increased as the supplementation level increased. The nutritional properties of sample showed that enrichment of semolina with MPI had a pronounced effect on lysine, cysteine, arginine, and histidine contents. All computed nutritional indices were higher in enriched samples compared to the control. Color measurement of sample showed that a and b values increased and L value decreased as the supplementation level increased. The SEM of different samples shows that enrichment of pasta with MPI increases the matrix around starch granules.

Effect of detoxification of castor seed (Ricinus communis) protein isolate on its nutritional quality.

Nutritional quality of the castor meal protein isolate detoxified using boiling and lime cum heat treatments was evaluated in experiments with rats. Chemical scores of both the treated isolates were similar, threonine being the first limiting amino acid. The calculated nutritional indices (essential amino acid index) and PER were higher for the boiled isolate (1.3) than that was for lime-cum-heat treated (0.86). Though, necropsy examination of organs did not reveal any abnormalities, histopathological changes were observed in the organs-liver, kidney, intestine that could be attributed to the deficiency of essential amino acids in the detoxified castor protein isolates.

Effect of different proteolytic enzymes on the nature of subunit composition of arachins from groundnut (Arachis hypogaea L.).

Arachin, the major protein from groundnut, was isolated from three varieties of groundnut (Spanish Improved, TMV-2 and DH-3-30) using a modified procedure involving precipitation with 18% ammonium sulphate to obtain homogeneous protein. The homogeneity was judged by polyacrylamide gel electrophoresis, gel filtration and sedimentation velocity techniques as well as correlation with amino acid composition. Rates of hydrolysis of arachins by trypsin (pH 7.6) and alpha-chymotrypsin (pH 7.8) were significantly different between the three varieties. Arachin from the Spanish Improved variety contained higher amounts of alanine and phenylalanine and lower amounts of carbohydrate and phosphorus as compared to TMV-2 and DH-3-30. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis pattern of arachin from TMV-2 showed only seven bands of which the ones with low molecular weight were more intense than those of the other two varieties. The far-ultraviolet circular dichroic spectra showed no significant differences among the three varieties in respect of alpha-helix content (5 +/- 2%), beta-structure (19 +/- 2%) and the aperiodic structure. The observed differences in hydrolysis rates have been explained as due to the differences in the acidic and basic subunits of arachins.