Cutin and Cutan Biopolymers: Their Role as Natural Sorbents

• Published in: Soil Science Society of America journal Vol. 74; no. 4; pp. 1139 - 1146
• Main Authors: Shechter, Michal, Xing, Baoshan, Chefetz, Benny
• Format: Journal Article
• Language: English
• Published: Madison Soil Science Society 01.07.2010; Soil Science Society of America; American Society of Agronomy
• Subjects: Agronomy. Soil science and plant productions; aliphatic biopolymers; Biodegradation; Biological and medical sciences; Biopolymers; Carbon; Carbon 13; cutan; cutin; Decomposition; Desorption; differential scanning calorimetry; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; humic substances; hysteresis; Loam soils; NMR; Nuclear magnetic resonance; nuclear magnetic resonance spectroscopy; Organic compounds; Organic matter; Phenanthrene; soil biochemistry; Soil organic matter; Soil science; Soils; Sorbents; Sorption; sorption isotherms; Studies; Surficial geology; temporal variation; Soil science; Earth science; Natural; Sorbent; Biopolymer
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj2009.0313

The aliphatic biopolymers cutin and cutan are important precursors of soil organic matter. In this study, we examined the effects of these biopolymers' decomposition and transformation in the soil on their sorptive properties. The levels of cutin and cutan decreased by 35 and 30%, respectively, after 20 mo of incubation. Carbon-13 nuclear magnetic resonance and differential scanning calorimeter analyses suggested that the rigid (crystalline) polymethylene moieties of cutan decompose with time. This observation is in contrast to previous reports, which suggested that this alkyl-C moiety is resistant to biodegradation. Cutin, however, exhibited mainly decomposition of the mobile (amorphous) polymethylene moieties. Moreover, some of its degraded materials were transformed into humic materials. The phenanthrene sorption coefficient decreased by 80 and 37% with incubation time of the cutin and cutan samples, respectively. For 1-naphthol, the sorption capacity decreased by 90% due to cutin decomposition. With cutan, this parameter did not show any changes correlated with incubation time. Phenanthrene exhibited linear and reversible sorption isotherms. In contrast, pronounced desorption hysteresis was obtained for 1-naphthol with the 20-mo-incubated cutin sample and with all cutan samples. With all cutan samples, desorption hysteresis increased with decomposition. Our data suggest that the sorptive nature of both biopolymers was affected by soil decomposition. With degradation, the role of cutin as a natural sorbent decreases while cutan acts as a natural highly efficient sorbent for organic compounds in the soil.