Biology subjects

Lott, C.

Publications and source records attributed to Lott, C..

4 recordsLinked to original sources

bioRxiv2025

Native and regenerated cellulose show similar environmental biodegradation behavior across global terrestrial and aquatic ecosystems

Cellulose is the most abundant natural polymer and serves as the structural scaffolding molecule of plants, and materials from cellulose fibers are considered important to the global shift toward renewable materials. Yet, uncertainty remains about their persistence in natural environments. Here we show that native and regenerated cellulose, ranging from cotton and linen to viscose, modal, and lyocell, despite minor structural differences, are biodegraded at comparable rates, indicating that there is no scientifically justified distinction regarding environmental behavior. We assessed the biodegradation of diverse cellulosic materials, including powders, loose fibers, fabrics, and nonwovens, under technical and natural conditions across soil, home compost, freshwater, and marine coastal and deep-sea environments. Our study combined a total of 152 scenarios with laboratory tests, mesocosm and field experiments, spanning from polar to tropical regions and temperatures from -1.8 {degrees}C in the high Arctic Ocean to 38.4 {degrees}C in a marine beach in the Mediterranean Sea, and between -6.1 to 54.1 {degrees}C in agricultural soil. All neat cellulosic fibers showed inherent biodegradability, with biodegradation half-lives typically ranging from weeks to months. Biodegradation rates were primarily driven by water availability, temperature, and nutrient levels, while the role of oxygen was indifferent. Standardized lab tests aligned well with field observations, confirming their validity for assessing inherent biodegradability with environmental relevance. However, biodegradation of biodegradable polymers in real-world scenarios is influenced by product-level modifications such as dyeing and finishing. By distinguishing the effects of fiber chemistry separately from those of finishing treatments, this study clarifies the role of cellulose in a sustainable materials economy and supports evidence-based regulation of fiber biodegradability claims and product labeling.

microbiology↗

bioRxiv2023

Mechanism of high energy efficiency of carbon fixation by sulfur-oxidizing symbionts revealed by single-cell analyses and metabolic modeling

In chemosynthetic symbioses between marine invertebrates and autotrophic sulfur-oxidizing bacteria the symbionts feed their host by producing organic compounds from CO2 using reduced sulfur compounds as an energy source. One such symbiosis, the gutless marine worm Olavius algarvensis harbors at least five bacterial symbionts of which four have the genetic potential for an autotrophic metabolism. In this study we combined single-cell analyses of CO2 fixation, CO2 release and bulk uptake, with measurements of O2 respiration, sulfur content, and polyhydroxyalkanoate content, as well as mathematical modelling to investigate how energy derived from sulfur oxidation drives carbon fluxes within the symbiosis and between the holobiont and its habitat. We found that under aerobic conditions without external energy sources only the primary symbiont, Ca. Thiosymbion algarvensis, fixed carbon. This symbiont relied on internal sulfur storage for energy production. Our model showed that the apparent efficiency of carbon fixation driven by sulfur oxidation in the symbiosis was higher than thermodynamically feasible if only stored sulfur was considered as source of energy and reducing equivalents. The model and additional calculations showed that reducing equivalents must be derived from a different source than energy. We identified the large amounts of polyhdroxyalkanoate stored by the symbiont as the likely source of reducing equivalents for carbon fixation in the symbiont which boosts the yield of sulfur-driven carbon fixation. The model also showed that heterotrophic carbon fixation by host tissue is not negligible and has to be considered when assessing transfer of carbon from the symbionts to the host.

microbiology↗

bioRxiv2021

Half-life of biodegradable plastics in the marine environment depends on material, habitat, and climate zone

The performance of the biodegradable plastic materials polyhydroxyalkanoate (PHA), polybutylene sebacate (PBSe) and polybutylene sebacate co-terephthalate (PBSeT), and of polyethylene (LDPE) was assessed under marine environmental conditions in a three-tier approach. Biodegradation lab tests (20 {degrees}C) were complemented by mesocosm tests (20 {degrees}C) with natural sand and seawater and by field tests in the warm-temperate Mediterranean Sea (12 - 30 {degrees}C) and in tropical Southeast Asia (29 {degrees}C) in three typical coastal scenarios. Plastic film samples were exposed in the eulittoral beach, the pelagic open water and the benthic seafloor and their disintegration monitored over time. We used statistical modelling to predict the half-life for each of the materials under the different environmental conditions to render the experimental results numerically comparable across all experimental conditions applied. The biodegradation performance of the materials differed by orders of magnitude depending on climate, habitat and material and revealed the inaccuracy to generically term a material marine biodegradable. The half-life t0.5 of a film of PHA with 85 m thickness ranged from 54 d on the seafloor in SE Asia to 1247 d in mesocosm pelagic tests. t0.5 for PBSe (25 m) ranged from 99 d in benthic SE Asia to 2614 d in mesocosm benthic tests, and for PBSeT t0.5 ranged from 147 d in the mesocosm eulittoral to 797 d in Mediterranean benthic field tests. For LDPE no biodegradation could be observed. These data can now be used to estimate the persistence of plastic objects should they end up in the marine environments considered here and will help to inform the life cycle (impact) assessment of plastics in the open environment.

microbiology↗

bioRxiv2020

Field and mesocosm test methods to assess the performance of biodegradable plastic under marine conditions

The pollution of the natural environment, especially the worlds oceans, with conventional plastic is of major concern. Biodegradable plastics are an emerging market bringing along potential chances and risks. The fate of these materials in the environment and their possible effects on organisms and ecosystems has rarely been studied systematically and is not well understood. For the marine environment, reliable field test methods and standards for assessing and certifying biodegradation to bridge laboratory respirometric data are lacking. In this work we present newly developed field tests to assess the performance of (biodegradable) plastics under natural marine conditions. These methods were successfully applied and validated in three coastal habitats (eulittoral, benthic and pelagic) and two climate zones (Mediterranean Sea and tropical Southeast Asia). Additionally, a stand-alone mesocosm test system which integrated all three habitats in one technical system at 400-L scale independent from running seawater is presented as a methodological bridge. Films of polyhydroxyalkanoate copolymer (PHA) and low density polyethylene (LD-PE) were used to validate the tests. While LD-PE remained intact, PHA disintegrated to a varying degree depending on the habitat and the climate zone. Together with the existing laboratory standard test methods, the field and mesocosm test systems presented in this work provide a 3-tier testing scheme for the reliable assessment of the biodegradation of (biodegradable) plastic in the marine environment. This toolset of tests can be adapted to other aquatic ecosystems.

ecology↗