A simple and effective set of PCR-based molecular markers for the monitoring of the Saccharomyces cerevisiae cell population during bioethanol fermentation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)One of the defining features of the fermentation process used in the production of bioethanol from sugarcane feedstock is the dynamic nature of the yeast population. Minisatellite molecular markers are particularly useful for monitoring yeast communities because they produce polymorphic PCR products that typically display wide size variations. We compared the coding sequences derived from the genomeof the sugarcane bioethanol strain JAY270/PE-2 to those of the reference Saccharomyces cerevisiae laboratory strain S288c, and searched for genes containing insertion or deletion polymorphisms larger than 24 bp. We then designed oligonucleotide primers flanking nine of these sites, and used them to amplify differentially sized PCR products. We analyzed the banding patterns in the most widely adopted sugarcane bioethanol strains and in several indigenous yeast contaminants, and found that our marker set had very good discriminatory power. Subsequently, these markers were used to successfully monitor they east cell populations in six sugarcane bioethanol distilleries. Additionally, we showed that most of the markers described here are also polymorphic among strains unrelated to bioethanol production, suggesting that they may be applied universally in S. cerevisiae. Because the relatively large polymorphisms are detectable in conventional agarose gels, our method is well suited to modestly equipped on-site laboratories at bioethanol distilleries, therefore providing both cost and time savings. (C) 2013 Elsevier B.V. All rights reserved.1684701709Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Colorado State University Clean Energy SuperclusterFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Humic-like bioactivity on emergence and early growth of maize (Zea mays L.) of water-soluble lignins isolated from biomass for energy

Lignin of lignocellulosic residues from biomass for energy can be exploited in sustainable agriculture as plant stimulants. Lignin monomers or their microbial bioproducts are mainly responsible for the plant growth promotion exerted by humic matter in soil. The aim of this work was to verify the humic-like bioactivity of water-soluble lignin isolated from biomass for energy towards plant growth and relate the biostimulation to the lignin molecular structure. Two water-soluble lignins isolated from giant reed (AD) and miscanthus (MG) were characterized for molecular composition by H-1 and P-31 1D-, C-13-H-1 2D-, DOSY-NMR spectroscopy and for conformational structure by size-exclusion chromatography. The effect of different aqueous concentrations of lignin on germination of maize seeds and growth of maize plantlets was assessed in growth-chamber experiments. Both lignins showed humic-like supramolecular structures, but different conformational stability and molecular composition. Their largest bioactivity was revealed at 10 and 50 ppm of lignin organic carbon and both significantly increased length of radicles, lateral seminal roots, and coleoptiles of maize seedlings, as well as total shoot and root dry weights and root length of maize plantlets. However, differences in AD and MG bioactivity were attributed to their conformational stabilities and content of amphiphilic molecules, which may control both the adhesion to plant roots and the release of bioactive molecules upon interactions with plant-exuded organic acids. The humic-like bioactivity of water-soluble lignins indicated that lignocellulosic residues from energy crops may be profitably recycled in agriculture as effective plant growth promoters, thereby increasing the economic and environmental sustainability of energy production from non-food biomasses