scholarly journals Construction of advanced producers of first- and second-generation ethanol in Saccharomyces cerevisiae and selected species of non-conventional yeasts (Scheffersomyces stipitis, Ogataea polymorpha)

2019 ◽  
Vol 47 (1) ◽  
pp. 109-132 ◽  
Author(s):  
Justyna Ruchala ◽  
Olena O. Kurylenko ◽  
Kostyantyn V. Dmytruk ◽  
Andriy A. Sibirny
Keyword(s):  
Saccharomyces Cerevisiae ◽  
First Generation ◽  
Second Generation ◽  
Ethanol Tolerance ◽  
Ethanol Yield ◽  
Scheffersomyces Stipitis ◽  
Ethanol Producer ◽  
First And Second Generation ◽  
Ogataea Polymorpha ◽  
Second Generation Ethanol

Abstract This review summarizes progress in the construction of efficient yeast ethanol producers from glucose/sucrose and lignocellulose. Saccharomyces cerevisiae is the major industrial producer of first-generation ethanol. The different approaches to increase ethanol yield and productivity from glucose in S. cerevisiae are described. Construction of the producers of second-generation ethanol is described for S. cerevisiae, one of the best natural xylose fermenters, Scheffersomyces stipitis and the most thermotolerant yeast known Ogataea polymorpha. Each of these organisms has some advantages and drawbacks. S. cerevisiae is the primary industrial ethanol producer and is the most ethanol tolerant natural yeast known and, however, cannot metabolize xylose. S. stipitis can effectively ferment both glucose and xylose and, however, has low ethanol tolerance and requires oxygen for growth. O. polymorpha grows and ferments at high temperatures and, however, produces very low amounts of ethanol from xylose. Review describes how the mentioned drawbacks could be overcome.

Genetic Enhancement of Saccharomyces Cerevisiae for First and Second Generation Ethanol Production

2017 ◽  
pp. 239-279
Author(s):  
Fernanda Bravim ◽  
Melina Campagnaro Farias ◽  
Oeber De Freitas Quadros ◽  
Patricia Machado Bueno Fernandes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Second Generation ◽  
Genetic Enhancement ◽  
First And Second Generation ◽  
Second Generation Ethanol

Comparison of Spathaspora passalidarum and recombinant Saccharomyces cerevisiae for integration of first- and second-generation ethanol production

2021 ◽  
Vol 21 (6) ◽  
Author(s):  
Isabela de Oliveira Pereira ◽  
Ângela Alves dos Santos ◽  
Davi L Gonçalves ◽  
Marcela Purificação ◽  
Nick Candiotto Guimarães ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Second Generation ◽  
Ethanol Yield ◽  
Fractionation Process ◽  
Sucrose Hydrolysis ◽  
Recombinant Saccharomyces Cerevisiae ◽  
Hemicellulosic Hydrolysate ◽  
Spathaspora Passalidarum ◽  
Microaerobic Conditions ◽  
Second Generation Ethanol

ABSTRACT First-generation ethanol (E1G) is based on the fermentation of sugars released from saccharine or starch sources, while second-generation ethanol (E2G) is focused on the fermentation of sugars released from lignocellulosic feedstocks. During the fractionation process to release sugars from hemicelluloses (mainly xylose), some inhibitor compounds are released hindering fermentation. Thus, the biggest challenge of using hemicellulosic hydrolysate is selecting strains and processes able to efficiently ferment xylose and tolerate inhibitors. With the aim of diluting inhibitors, sugarcane molasses (80% of sucrose content) can be mixed to hemicellulosic hydrolysate in an integrated E1G–E2G process. Cofermentations of xylose and sucrose were evaluated for the native xylose consumer Spathaspora passalidarum and a recombinant Saccharomyces cerevisiae strain. The industrial S. cerevisiae strain CAT-1 was modified to overexpress the XYL1, XYL2 and XKS1 genes and a mutant ([4–59Δ]HXT1) version of the low-affinity HXT1 permease, generating strain MP-C5H1. Although S. passalidarum showed better results for xylose fermentation, this yeast showed intracellular sucrose hydrolysis and low sucrose consumption in microaerobic conditions. Recombinant S. cerevisiae showed the best performance for cofermentation, and a batch strategy at high cell density in bioreactor achieved unprecedented results of ethanol yield, titer and volumetric productivity in E1G–E2G production process.

A Yeast Isolated from Cashew Apple Juice and Its Ability to Produce First- and Second-Generation Ethanol

2014 ◽  
Vol 174 (8) ◽  
pp. 2762-2776 ◽  
Author(s):  
E. M. Barros ◽  
T. H. S. Rodrigues ◽  
A. D. T. Pinheiro ◽  
A. L. Angelim ◽  
V. M. M. Melo ◽  
...  
Keyword(s):  
Apple Juice ◽  
Second Generation ◽  
Cashew Apple Juice ◽  
Cashew Apple ◽  
First And Second Generation ◽  
Second Generation Ethanol

Assimilation of the Puerto Ricans on the Mainland

1968 ◽  
Vol 2 (2) ◽  
pp. 21-39
Author(s):  
John J. Macisco
Keyword(s):  
United States ◽  
First Generation ◽  
Second Generation ◽  
Puerto Ricans ◽  
The United States ◽  
Social Scientists ◽  
First Marriage ◽  
Labor Force Status ◽  
Age At First Marriage ◽  
First And Second Generation

Social scientists have repeatedly tried to specify the process whereby assimilation takes place. This article points out the value of socio-demographic analysis in the study of assimilation, by describing the characteristics of Puerto Ricans on the United States mainland. In order to assess the direction of change between the first and second generation Puerto Ricans, data for the total United States population are also presented. Most of the data are drawn from the 1960 Census. First generation Puerto Ricans are compared with the second generation along the following dimensions: age, education, labor force status, income, occupation, age at first marriage, percent outgroup marriage and fertility. The Author concludes that second generation Puerto Ricans are moving in the direction of total United States averages.

scholarly journals Evaluation of polyploid miscanthus lines usage efficiency as a feedstock for bioethanol production

2021 ◽  
Vol 29 ◽  
pp. 13-19
Author(s):  
R. Y. Blume ◽  
O.V. Melnychuk ◽  
S.P. Ozheredov ◽  
D.B. Rakhmetov ◽  
Y.B. Blume
Keyword(s):  
Sweet Sorghum ◽  
Second Generation ◽  
Ethanol Yield ◽  
Bioenergy Crops ◽  
Control Line ◽  
Bioethanol Production ◽  
Second Generation Bioethanol ◽  
Giant Miscanthus ◽  
First And Second Generation ◽  
Bioethanol Yield

Aim. Main aim of this research was the evaluation of theoretical bioethanol yield (per ha) from hexaploid giant miscanthus (Miscanthus х giganteus) and further comparison with conventional triploid form as well as with other bioethanol crops. Methods. Several mathematic functions were determined that describe yearly yield dynamics and equations, which were used in calculations of theoretical bioethanol yield. Results. The theoretical bioethanol yield was evaluated for different hexaploid miscanthus lines. The most productive in terms of ethanol yield were lines 108 and 202, from which potential bioethanol yield was found to be higher than in control line (6451 L/ha) by 10.7 % and 14.2% respectively and can reach 7144 L/ha and 7684 L/ha. Conclusions. It was determined that the most productive lines of polyploid miscanthus (lines 108 and 202) are able to compete with other plant cellulosic feedstocks for second-generation bioethanol production in Ukraine. However, these lines show bioethanol productivity than sweet sorghum, in the case when sweet sorghum is processed for obtainment of both first- and second-generation bioethanol. Keywords: bioenergy crops, biofuels, giant miscanthus, Miscanthus, polyploidy, second-generation bioethanol.

scholarly journals Why do first and second-generation young migrants volunteer? The Migrant Volunteerism Motivation Model (MVMM)

2019 ◽  
Vol 7 (2) ◽  
pp. 1089-1107 ◽  
Author(s):  
Sara Alfieri ◽  
Daniela Marzana ◽  
Sara Martinez Damia
Keyword(s):  
Transition To Adulthood ◽  
Process Model ◽  
First Generation ◽  
Second Generation ◽  
Maintenance Phase ◽  
Structured Interviews ◽  
Sub Saharan ◽  
Italian Context ◽  
First And Second Generation ◽  
Motivation Model

The following study aims at inquiring into the motivations behind young migrants’ volunteerism in civic organizations in Italy, namely in starting and maintaining their engagement (preliminary vs. maintenance phase). The term “young migrants” refers to first and second generation of migrants who deal with two challenges: the transition to adulthood and the acquisition of a cultural identity. We conducted semi-structured interviews with 37 Sub-Saharan young migrants living in Italy (18-32 years old), 19 of first generation (1G) and 18 of second generation (2G). The Omoto and Snyder’s Volunteer Process Model (VPM, 1995) was used as an underpinning theoretical framework and a guide for the interpretations of the results. The findings indicate that a) motivations included in the VPM are also found for young migrants, b) some of these motivations take particular meaning for young migrants, c) some motivations are not included in the VPM and are specific of this sample. We named these last motivations: social norms, advocacy and ethno-cultural. In addition, some considerations may be advanced regarding the generation and the phase of motivation: 1G migrants are particularly moved by the importance of integration in the Italian context and by the promotion of their ethnic group while 2G migrants reported mostly the desire to understand their roots. The values, the concern for the community and the longing to develop relationships are the motivations for which all young migrants continue to volunteer; however, 1G migrants are also sustained by advocacy and ethno-cultural motivations. Implications and future directions are discussed.

scholarly journals The performance and genetic variation of first and second generation tropical alfalfa (Medicago sativa)

2021 ◽  
Vol 22 (6) ◽  
Author(s):  
Bambang Suwignyo ◽  
LUKMANA ARIFIN ◽  
NAFIATUL UMAMI ◽  
MUHLISIN MUHLISIN ◽  
BAMBANG SUHARTANTO
Keyword(s):  
Organic Matter ◽  
Genetic Variation ◽  
Medicago Sativa ◽  
Crude Protein ◽  
Dry Matter ◽  
First Generation ◽  
Second Generation ◽  
Seed Viability ◽  
Nutrient Content ◽  
First And Second Generation

Abstract. Suwignyo B, Arifin L, Umami N, Muhlisin, Suhartanto B. 2021. The performance and genetic variation of first and second generation tropical alfalfa (Medicago sativa). Biodiversitas 22: 3265-3270. This study aimed to compare the growth performance, nutrient content, seed viability, and genetic variation of first- and second-generation alfalfa (Medicago sativa L.). First and second-generation alfalfa seeds were obtained from the Forage and Pasture Science Laboratory, Department of Animal Nutrition and Feed Science, Faculty of Animal Science, Universitas Gadjah Mada (UGM), Yogyakarta, Indonesia. First generation alfalfa (F1) seeds were obtained from cross breeding of two different parental alfalfa varieties, namely, Canadian and local. The second-generation (F2) seeds were obtained from plants of the first-generation alfalfa (F1). A randomized design experiment was conducted using the two types of alfalfa (first- and second generation). Alfalfa from Canada as female parent was used as the baseline in the genetic masker test. Seeds were planted in a polybag, watered twice a day, and received 12 hours of daylight and 4 hours of artificial light. Plants were then harvested 8 weeks after planting by cutting the plant canopy. Genetic variation was examined using the Inter Simple Sequence Repeat (ISSR) method followed by descriptive analysis. Germination, plant height, dry matter content, organic matter, and crude protein were assessed as variables using a Student’s T-test. Our results showed that germination, plant height, leaf color, and nutrient content (dry matter, organic matter, and crude protein) of the first- and second-generation alfalfa plants were not significantly different. However, the second-generation alfalfa demonstrated better seed viability than the first generation plants, then it can be categorized as a new genotype (tropical alfalfa) based on genetic variation analysis.

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