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Petya Stoykova

Agrobioinstitute

Publishes on Algal biology and biofuel production, Biocrusts and Microbial Ecology, Spectroscopy and Chemometric Analyses. 17 papers and 582 citations.

17Publications
582Total Citations

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Top publicationsby citations

Psychological Capital Intervention (<scp>PCI</scp>): A Replication and Extension
Silvia Dello Russo, Petya Stoykova|Human Resource Development Quarterly|2015
Cited by 187Open Access

Psychological Capital (PsyCap) is a positive individual characteristic, and its malleability and openness to development have made it the focus of considerable attention in recent years. A training procedure for improving individuals’ PsyCap has been advanced and tested by Luthans and colleagues in a North American sample. The purpose of the current study was to generalize the effectiveness of the PsyCap Intervention (Luthans, Avey, Avolio, Norman, &amp; Combs, 2006) when conducted by different trainers (i.e., replication), and to explore its longer term effects (i.e., extension). We trained a pooled sample ( N = 40) of students and professionals in Bulgaria and conducted a one‐month follow‐up assessment of PsyCap in order to examine the durability of the training effects. The statistical analyses revealed significant improvements in the overall PsyCap after training as well as in each of its four dimensions, namely, self‐efficacy, hope, resilience, and optimism; remarkably, these improvements remained stable over one month, attesting to the durability of the training effects in the samples of both students and professionals. These results contribute to the accrual of scientific knowledge on a theory‐driven and evidence‐based HRD intervention.

Review on the biotechnological and nanotechnological potential of the streptophyte genus<i>Klebsormidium</i>with pilot data on its phycoprospecting and polyphasic identification in Bulgaria
Maya Stoyneva‐Gärtner, Blagoy Uzunov, Georg Gärtner et al.|Biotechnology & Biotechnological Equipment|2019
Cited by 17Open Access

This review provides data on the possibilities for commercial use of algae of the green streptophyte genus Klebsormidium. It is one of the basal algal progenitors of land plants and shows many mechanisms and features which allow its adaptation to different environmental stresses associated with land colonization. This has led to formation of structures and compounds with countless possible applications in biotechnology and nanotechnology, starting from food to pharmaceuticals and biofuels. Therefore, the present work aims to provide: (1) a review on this yet neglected topic for the first time; (2) reliable identification using the polyphasic taxonomic approach of three local Klebsormidium strains isolated from soils of two protected areas in Bulgaria (Kresnendko Defile and National park Rila). It also outlines the cultivation advantages of Klebsormidium broad tolerance to harsh conditions and its reproductive features (easy disintegration and possibility to produce resting stages). The possibility to use inoculum of akinetes in soil algalization as biofertilizers is proposed. The results from standard microscopical identification and molecular data (ITS and rbcL, used separately and in combination), combined in the applied polyphasic approach led to distinguishing between geographically distinct strains collected at different altitudes. After identification of two strains (ACUS 00001 and ACUS 00014) as belonging to Klebsormidium dissectum and of ACUS 00207 as belonging to Klebsormidium klebsii, the similarity of the latter taxon with K. nitens is discussed.

Carotenoids in five aeroterrestrial strains from<i>Vischeria/Eustigmatos</i>group: updating the pigment pattern of Eustigmatophyceae
Maya Stoyneva‐Gärtner, Petya Stoykova, Blagoy Uzunov et al.|Biotechnology & Biotechnological Equipment|2019
Cited by 16Open Access

Carotenoids have received particular attention both for their importance in algal systematics and hydrobiology and for their health benefits for humans, along with other applications in various industries. Here, we provide new data on the carotenoid content of five Vischeria/Eustigmatos strains isolated from aeroterrestrial habitats in Bulgaria and kept in the Algal Collection of Sofia University (ACUS). The obtained pigment pattern with nine carotenoids and generalization of literature data allowed us to update the knowledge on the chemotaxonomic characteristics of Eustigmatophyceae with a total of 47 pigments reported for the group, out of which 37 are carotenoids. The important photosynthetic pigment lutein, considered also a high-value product with extensive applications in feed, food, nutraceutical and pharmaceutical industries, was proved as a novel carotenoid for the group. The results also confirmed the presence of luteoxanthin, which is rarely reported in algae. All strains had a high content of the commercially valuable health-promoting xanthophyll astaxanthin. There were also different amounts of beta-carotene, violaxanthin, vaucheriaxanthin, canthaxanthin, zeaxanthin and antheraxanthin. Based on the differences in the pigment composition of the members of the ecological groups of aquatic and aeroterrestrial species, we propose the existence of two main pigment types in the class Eustigmatophyceae, with the aquatic type further divided into freshwater and marine pigment subtypes.