Protein hydrolysates (PHs) are organic non-microbial biostimulants having beneficial effects on plants. The study was designed to assess the effects on plants by the applications of PHs obtained from Trichoderma isolates grown on keratin wastes. Trichoderma isolates were characterized for indole-3-acetic acid and siderophores production, activity of lytic enzymes, phosphorous solubilization and inhibition of pathogens growth, using qualitative specific tests. Fungal isolates were cultured on a medium with keratin wastes (wool and feathers) to obtain PHs. Fungal PHs were tested in vivo for plant biostimulant action, as follows: (i) seeds germination test; (ii) activation of plant proton pump; (iii) evaluation of effect on tomato seedling growth. PHs from T. asperellum cultured on feathers medium reached the highest values for all parameters recorded (plant height and diameter, number of leaves and branches), with the exception of those for plant biomass, which were maximum for the wool medium. The metabolites released by keratin degradation under the activity of selected T. asperellum isolate improved crop health and productivity. The use of PHs can be a reasonable solution for the environmental pollution of by-products from the food chain, as well as for the replacement of chemical fertilizers with microbial formulations to stimulate plant growth.

Polypropylene–cellulose composites have great potential in many important commercial applications, and it is important to understand and properly evaluate their biodegradative behavior to achieve improved composite formulations in accordance with their future applications. In the present study, an outdoor soil burial test was performed in order to evaluate the susceptibility to degradation of polyolefins–cellulose composites. The structural and morphological changes were analyzed by Fourier transform infra-red spectroscopy with attenuated total reflectance (FTIR-ATR) and scanning electron microscopy (SEM). The weight loss of composite samples after burying in soil was recorded. The presence of new bands, as an indicator of degradation, was confirmed by FTIR-ATR spectra. The thermal stability of the composites after soil burial analyzed by TGA was slightly improved, with relatively higher temperatures being required to decompose the samples after exposure to environmental factors. SEM micrographs presented some modifications of the polymer surface, such as holes, cracks, exfoliations, and fractures. Increasing the cellulose percentage of the composite samples led to increased weight loss. From the obtained results, it can be concluded that composites based on polyolefins and renewable resources undergo a slow process of biodegradation after contact with environmental microorganisms and, with appropriate composition, could be applied to various environmental fields.

Keratinophilic fungi are present in soil as decomposers of keratinous substrates, while keratinolytic fungi have the capacity to decompose native keratin, the insoluble fibrous proteins from living organism. Keratin materials, especially by-products from food industry and animal husbandry must be harnessed through innovative, non-polluting and low-cost solutions. The nonpathogenic keratinolytic fungal species produce extracellular keratinases which have many and various applications, one being in leather industry where dehairing process of skin and hides require keratinolytic activity. The present study investigates the biodegradative potential of selected keratinolytic fungal microorganisms expressed towards different types of animal skins. The ability of Fusarium sp. 1 A strain to produce keratinase with a good activity towards animal skins was confirmed. These results suggest that after further studies, Fusarium sp.1A could play an important role in processing of animal wastes.

In the present study, several selected formulations based on recycled (rPP) or virgin polyolefins (vPP) and lignocelluloses were prepared and subjected to microorganism attack. Biodegradation tests were performed with microbial strains belonging to fungal genera, like Aspergillus, Penicillium and Fusarium. The initiation of biodegradation was demonstrated by Scanning Electron Microscope (SEM) micrographs showing the colonization of surface samples by microbial strains. The crystallinity of composites calculated based on Differential Scanning Calorimetry (DSC) curves evidenced some fluctuations as effect of biodegradation process. The most significant increase of crystallinity was obtained for v(PP)-wood samples, from 35.4% (sample without microbial contact) to 58.84% (sample incubated with Fusarium), 47.97 % (sample incubated with Penicillium) and 51.37 % (incubation with Aspergillus), respectively. The microbial activity upon rPP based composites did not induce significantly changes of crystallinity. Fourier Transform Infrared Analysis (FTIR) showed the increase of the peak corresponding to the carbonyl group at 1740 cm -1 that indicated the oxidative reactions in the chain in polymer matrix. Also there were observed new bands at 1647-1651, 1547 cm -1 assigned to protein materials from microorganisms, and at 1046-1450 cm -1 assigned to polysaccharides. The results showed that the some polymeric composites suffered a slowly biodegradative process, the process depending on polymer characteristics (structure, complexity, composition) and microorganism ability. From the obtained results, it can be concluded that Aspergillus strain is active in the biodegradation of tested composites.

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