Browsing by Autor "Carla Crespo"

Now showing 1 - 6 of 6

Brewery spent yeast medium for Serratia sp. bio-beads improves Chenopodium quinoa Willd. growth in the Northern Altiplano of Bolivia
(Oxford University Press, 2025) Ximena Ramirez; V. S. Gonzales; Rogelio Maydana; Mukesh Dubey; Dan Funck Jensen; Cristhian Carrasco; Magnus Karlsson; Carla Crespo
Quinoa (Chenopodium quinoa Willd.) is a climate-resilient Andean crop with high nutritional value and strategic importance for food security in high-altitude regions. However, its productivity in low-input farming systems remains limited. This study developed scalable strategies for propagation and formulation of a Serratia sp. strain as a biofertilizer, using brewery spent yeast (BSY) as growth substrate. Microwave-assisted extraction (MAE) at 1200 W for 15 min significantly (P ≤ 0.05) enhanced soluble protein release from BSY, and MAE-treated media with a C:N ratio of 24:1 supported optimal bacterial growth. Carrageenan-based bio-bead formulations produced at 40°C with 96 g L⁻¹ carrageenan yielded the highest bacterial viability and moisture retention. In a field trial in the Bolivian Altiplano, bio-beads containing Serratia sp. applied at branching stage increased quinoa yield by up to 3.4-fold (P ≤ 0.01) compared with the control. The formulation control also substantially improved yield (2.2-fold), indicating that both the carrier matrix and bacterial inoculation contributed to growth enhancement. These findings demonstrate the potential of biofertilizer technologies based on agri-food by-product valorization to improve crop performance under extreme and resource-limited agricultural conditions.
Caloramator boliviensis sp. nov., a thermophilic, ethanol-producing bacterium isolated from a hot spring
(Microbiology Society, 2011) Carla Crespo; Tania Pozzo; Eva Nordberg Karlsson; María Teresa Álvarez; Bo Mattìasson
A novel moderately thermophilic, anaerobic, ethanol-producing bacterial strain, 45B(T), was isolated from a mixed sediment water sample collected from a hot spring at Potosi, Bolivia. The cells were straight to slightly curved rods approximately 2.5 µm long and 0.5 µm wide. The strain was Gram-stain-variable, spore-forming and monotrichously flagellated. Growth of the strain was observed at 45-65 °C and pH 5.5-8.0, with optima of 60 °C and pH 6.5. The substrates utilized by strain 45B(T) were xylose, cellobiose, glucose, arabinose, sucrose, lactose, maltose, fructose, galactose, mannose, glycerol, xylan, carboxymethylcellulose and yeast extract. The main fermentation product from xylose and cellobiose was ethanol (0.70 and 0.45 g ethanol per gram of consumed sugar, respectively). Acetate, lactate, propionate, carbon dioxide and hydrogen were also produced in minor quantities. 1,3-Propanediol was produced when glycerol-containing medium was supplemented with yeast extract. The major cellular fatty acids were anteiso-C(15:0), C(16:0), iso-C(16:0), C(15:1), iso-C(14:0), C(13:0) and C(14:0). The polar lipids diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an aminoglycolipid and 15 other unidentified lipids were predominant. The DNA G+C content of strain 45B(T) was 32.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity revealed that strain 45B(T) is located within the Gram-type positive Bacillus-Clostridium branch of the phylogenetic tree. On the basis of morphological and physiological properties and phylogenetic analysis, strain 45B(T) represents a novel species, for which the name Caloramator boliviensis sp. nov. is proposed; the type strain is 45B(T) (=DSM 22065(T)=CCUG 57396(T)).
Diversity of Trichoderma in the unexplored Bolivian Amazon region and their potential for coffee diseases control
(Oxford University Press, 2025) Marisel M Mamani; Lilia Catacora; Nélida Nina; Wendy Daniela Tola Alarcon; Feng M Cai; Jesper Rydèn; Irina S. Druzhinina; Dan Funck Jensen; Carla Crespo; Magnus Karlsson
Trichoderma fungi are colonizers of plant substrates and rhizosphere and are valued for their antagonism against phytopathogens and ability to promote plant health. We investigated Trichoderma diversity in coffee-growing soils in Caranavi region of Yungas-La Paz, Bolivia, where high humidity and fungal diseases threaten yield, and evaluated their potential as biocontrol agents against coffee pathogens. A total of 440 Trichoderma were isolated from coffee rhizosphere, fallow lands, and forest ecosystems across an altitudinal gradient in Caranavi. DNA barcode analyses using ITS, rpb2, and tef1 loci identified only four species. However, 47 taxa comprising 344 isolates were ambiguous, and 41 isolates were previously unrecognised species. The diversity of Trichoderma spp. was significantly affected by ecosystem type and altitude, with more species isolated from coffee rhizosphere than fallow lands and forest ecosystems, and from lower altitudes than higher ones. Evaluation of 100 isolates against a native coffee wilt pathogen Fusarium oxysporum identified 70 potent antagonists, with 30 achieving 90-100% disease control. This is the first comprehensive study of Trichoderma diversity in Yungas, identifying indigenous Trichoderma for biocontrol applications against coffee diseases. It also emphasizes the need to refine the Trichoderma species concept and improve the taxonomic resolution within the genus.
Obtención de azucares reductores (glucosa) a partir en granos de quinua (Chenopodium quínoa) usando hidrólisis enzimática, ácida y el metabolismo de la embriogénesis vegetal
(2016) Juan José Amador Arze; Carla Crespo; Teresa Álvarez A
Precipitation of Zn(II), Cu(II) and Pb(II) at bench-scale using biogenic hydrogen sulfide from the utilization of volatile fatty acids
(Elsevier BV, 2006) María Teresa Álvarez; Carla Crespo; Bo Mattìasson
Rhizosphere bacteria from the Bolivian highlands improve drought tolerance in quinoa (Chenopodium quinoa Willd.)
(Oxford University Press, 2024) V. S. Gonzales; María Huallpan; Ximena Vargas-Ramírez; Yessica San Miguel; Mukesh Dubey; Dan Funck Jensen; Magnus Karlsson; Carla Crespo
Microorganisms from the arid Bolivian altiplano constitute a potential biological source of bioinoculants to improve quinoa productivity and provide sustainable mitigation of climate change effects.