4 research outputs found
Biodiversity does not enhance algal feedstock production when exposed to fungal infection: An experimental test in outdoor ponds using a before-after-control-impact (BACI) design
For outdoor cultivation of algal feedstocks to become a commercially viable and sustainable
option for biofuel production, algal cultivation must maintain high yields and temporal
stability in environmentally variable outdoor ponds. One of the main challenges is
mitigating disease outbreaks that leads to culture crashes. Drawing on predictions from the
âdilution effectâ hypothesis, in which increased biodiversity is thought to reduce disease risk
in a community, I tested whether algal polycultures would reduce disease risk and improve
feedstock production efficiencies compared to monocultures. While the positive benefits of
biodiversity on disease risk has been demonstrated in various systems, to the best of my
knowledge this is the first test in an algal biofuel system. Here, I present the results a
before-after-control-impact (BACI) experimental design comparing mean monoculture
(control) and polyculture (impact) yield, stability, and productivity before and after fungal
infection when grown in 400-L outdoor raceway ponds. I found that polycultures did not
experience a reduction in disease risk compared to monocultures or differ in production
efficiencies throughout the course of the 43-day experiment. These results show that
polyculture feedstocks can maintain similar levels of productivity, stability, and disease
resistance to that of a monoculture. Determining whether these results are generalizable or
represent one case study requires additional outdoor experiments using a larger variety of
host and pathogen species.Master of ScienceSchool for Environment and SustainabilityUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/167152/1/Widin_Spenser_Thesis.pd
Using a Microfluidic Gradient Generator to Characterize BG-11 Medium for the Growth of Cyanobacteria Synechococcus elongatus PCC7942
The photosynthetic cyanobacterium Synechococcus elongatus PCC7942 has recently gained great attention for its ability to directly convert CO2 into renewable chemicals upon genetic engineering. Thus, it is of great interest to increase the growth speed and lower the medium requirement for cultivating this cyanobacterium. The cultivation medium of Synechococcus elongatus PCC7942 has been developed, which consists of many inorganic and metal ingredients with a specific composition, known as the BG-11 medium. In this work, we analyzed the concentration effect of each ingredient and identified the absolutely essential components in BG-11 medium for cyanobacteria growth using the concentration gradient generator chip (CGGC) fabricated by MEMS technology. As shown by our results, removal of the individual component sodium nitrate, potassium phosphate, or magnesium sulfate from the BG-11 medium led to severe growth inhibition of Synechococcus elongatus PCC7942. Contrary to our expectation, increasing concentration of the crucial ingredients showed either insignificant or negative impact on cell growth. Overall, standard growth could be achieved without supplementation of ethylenediaminetetraacetic acid (EDTA) disodium, sodium carbonate, or sodium citrate to the culture medium. Further improvement of the CGGC-based microfluidic system based on this preliminary study may broaden its application range to analyze more complicated correlations
Using a Microfluidic Gradient Generator to Characterize BG-11 Medium for the Growth of Cyanobacteria Synechococcus elongatus PCC7942
The photosynthetic cyanobacterium Synechococcus elongatus PCC7942 has recently gained great attention for its ability to directly convert CO2 into renewable chemicals upon genetic engineering. Thus, it is of great interest to increase the growth speed and lower the medium requirement for cultivating this cyanobacterium. The cultivation medium of Synechococcus elongatus PCC7942 has been developed, which consists of many inorganic and metal ingredients with a specific composition, known as the BG-11 medium. In this work, we analyzed the concentration effect of each ingredient and identified the absolutely essential components in BG-11 medium for cyanobacteria growth using the concentration gradient generator chip (CGGC) fabricated by MEMS technology. As shown by our results, removal of the individual component sodium nitrate, potassium phosphate, or magnesium sulfate from the BG-11 medium led to severe growth inhibition of Synechococcus elongatus PCC7942. Contrary to our expectation, increasing concentration of the crucial ingredients showed either insignificant or negative impact on cell growth. Overall, standard growth could be achieved without supplementation of ethylenediaminetetraacetic acid (EDTA) disodium, sodium carbonate, or sodium citrate to the culture medium. Further improvement of the CGGC-based microfluidic system based on this preliminary study may broaden its application range to analyze more complicated correlations
Microbial stress. From sensing to intracellular and population responses
We initially devised this Research Topic (RT) as a valuable initiative to collect high-quality scientific articles from the participants of the 4th European Federation of Biotechnology (EFB) Microbial Stress meeting held in Kinsale, Ireland, April 2018. The scope of the RT is based on the scientific content of that âMicrobial Stress: from Systems to Molecules and backâ meeting. Indeed, over 40% of the articles eventually accepted for publication were contributed by meeting participants, but notably the remaining 60% was contributed by authors that work in this field. The collection of 22 original research and 2 review articles, contributed by 163 authors collectively, deal with the many different aspects of the microbial responses to biotic and abiotic stresses, relevant to many fields: from host-pathogen interactions to biotechnology, from bioremediation to food processing, from molecular and single-cell to population studies. The RT showcases the rapid developments of the microbial stress research on a range of microorganisms and stress conditions, and confirms that understanding microbial physiology under stress can be a trigger for the development of new methodologies as well as helping to integrate the knowledge from many different microbiological fields of research.
The retrospective analysis of the articles contributed to this RT allowed them to be assigned to one of four main sub-topics: (i) impact of weak organic acids and low pH on micro-organisms, from clinical to biotechnological contexts; (ii) adaptive responses in microbial pathogens to abiotic/environmental stress; (iii) oxidative and metal stress, from clinical to bioremediation
contexts, and (iv) regulation of transcription and translation under stress, from epigenetic aspects
to the role of second messengers and sRNA