ABSTACT:The preparation of new cellulose fiber reinforced thermoplastics is described, and the mechanical properties and water absorption of these materials are measured.In order to improve the compatibility between cellulosic and plastic materials, different amounts of coupling agents, such as organotitanate compounds, maleic anhydride copolymers and their combinations, are studied. As a filler, pine fiber, rose, carnation or coffee husk is used. Furthermore, the influence of the composition of the composites and the particle size of the filler on the material properties of the thermoplastics are investigated. The surface of the fractured samples is analyzed using scanning electron microscopy (SEM).

The understanding and manipulation of microbial communities toward the conversion of lignocellulose and plastics are topics of interest in microbial ecology and biotechnology. In this study, the polymer-degrading capability of a minimal lignocellulolytic microbial consortium (MELMC) was explored by genome-resolved metagenomics. The MELMC was mostly composed (>90%) of three bacterial members (Pseudomonas protegens; Pristimantibacillus lignocellulolyticus gen. nov., sp. nov; and Ochrobactrum gambitense sp. nov) recognized by their high-quality metagenome-assembled genomes (MAGs). Functional annotation of these MAGs revealed that Pr. lignocellulolyticus could be involved in cellulose and xylan deconstruction, whereas Ps. protegens could catabolize lignin-derived chemical compounds. The capacity of the MELMC to transform synthetic plastics was assessed by two strategies: (i) annotation of MAGs against databases containing plastic-transforming enzymes; and (ii) predicting enzymatic activity based on chemical structural similarities between lignin- and plastics-derived chemical compounds, using Simplified Molecular-Input Line-Entry System and Tanimoto coefficients. Enzymes involved in the depolymerization of polyurethane and polybutylene adipate terephthalate were found to be encoded by Ps. protegens, which could catabolize phthalates and terephthalic acid. The axenic culture of Ps. protegens grew on polyhydroxyalkanoate (PHA) nanoparticles and might be a suitable species for the industrial production of PHAs in the context of lignin and plastic upcycling.

The world market for compounds produced by biotechnological means is growing due to the search and implementation of cellular systems that allow the mass production of complex molecules with a specific biological activity. These range from drugs, to enzymes and proteins for diverse uses, such as academic research and the development of industrial processes. Pichia pastoris is a methylotrophic yeast that has been studied in recent decades for the expression and generation of recombinant proteins, because it has features that make it especially efficient, not only to host external DNA, but also to express it and, thus, produce a wide variety of molecules. In this study, the most important aspects related to the production of recombinant proteins are examined, by using P. pastoris as a model, from the most common expression strategy, to the aspects related to the cultivation at bioreactor scale and, by yielding high-value products. Some papers conducted, in Colombia, are also reviewed, as well as their approach and the current state of the expression system in the country's biotechnology and its barriers, by concluding that studies with P. pastoris are scarce and are mainly developed around a few academic centers.

Here, we report the complete genome sequence of the race 4 strain Xanthomonas campestris pv. campestris SB80, which was isolated from a symptomatic white head cabbage leaf in Samsun Province, Turkey, in 2019. The genome consists of a circular chromosome (5,129,762 bp) with a G+C content of 64.98%, for which 4,159 putative protein-coding genes, 2 rRNA operons, 54 tRNAs, and 86 noncoding RNAs (ncRNAs) were predicted.