ENVIRONMENTAL BIOTECHNOLOGY Native soil fungi associated with compostable plastics in three contrasting agricultural settings Jennifer Moore-Kucera & Stephen B. Cox & Mark Peyron & Graham Bailes & Kevin Kinloch & Kalin Karich & Carol Miles & Debra Ann Inglis & Marion Brodhagen Received: 1 January 2014 /Revised: 18 March 2014 /Accepted: 19 March 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract Plastics are used widely as agricultural mulches to suppress weeds and retain soil moisture. Disposal of conven- tional plastic mulches requires physical removal for disposal in a landfill or incineration. Biodegradable plastic mulches that could be tilled into the soil at the end of a growing season represent an attractive alternative to conventional plastic mulches. In this study, three commercially available mulches labeled as “biodegradable” and one experimental, potentially biodegradable mulch were used during a tomato growing season, and then buried in field soil at three locations for approximately 6 months, as would occur typically in an agri- cultural setting. Degradation after 6 months in soil was min- imal for all but the cellulosic mulch. After removal of mulches from soil, fungi were isolated from the mulch surfaces and tested for their ability to colonize and degrade the same mulches in pure culture. The majority of culturable soil fungi that colonized biodegradable mulches were within the family Trichocomaceae (which includes beneficial, pathogenic, and mycotoxigenic species of Aspergillus and Penicillium). These isolates were phylogenetically similar to fungi previously reported to degrade both conventional and biodegradable plastics. Under pure culture conditions, only a subset of fungal isolates achieved detectable mulch degradation. No isolate substantially degraded any mulch. Additionally, DNA was extracted from bulk soil surrounding buried mulches and ribosomal DNA was used to assess the soil microbial commu- nity. Soil microbial community structure was significantly affected by geographical location, but not by mulch treatments. Keywords Biodegradable plastic . Biodegradable polymers . Biodegradable mulch . Compostable plastic . Compostable mulch . Compostable polymers . Plastic-degrading fungi Introduction Plasticulture (the use of plastics in agriculture) dates back to the 1950s and includes plastic mulches (most commonly made of polyethylene) that warm the soil for early crop production, provide weed control, and retain soil moisture (Hill et al. 1982). However, polyethylene degrades very slow- ly (0.35 % in 2.5 years; Albertsson and Ranby 1979), and removal and disposal of single-use plastic is labor-intensive, expensive, and a growing ecological problem. Biodegradable Jennifer Moore-Kucera, Stephen B. Cox, and Mark Peyron contributed equally to this work. Electronic supplementary material The online version of this article (doi:10.1007/s00253-014-5711-x) contains supplementary material, which is available to authorized users. J. Moore-Kucera Department of Plant and Soil Science, Texas Tech University, 15th and Detroit, Room 201, Mail Stop 2122, Lubbock, TX 79409-3121, USA S. B. Cox Research and Testing Laboratory, LLC, 4321 Marsha Sharp FWY, Door #2, Lubbock, TX 79407, USA M. Peyron Department of Chemistry, Western Washington University, 516 High Street, Bellingham, WA 98225-9150, USA G. Bailes : K. Kinloch : M. Brodhagen (*) Biology Department, Mailstop 9160, Western Washington University, 516 High Street, Bellingham, WA 98225-9150, USA e-mail: Marion.Brodhagen@wwu.edu K. Karich Department of Engineering Technology, Western Washington University, 516 High Street, Bellingham, WA 98225-9150, USA C. Miles : D. A. Inglis Northwestern Washington Research & Extension Center, Washington State University, 16650 State Route 536, Mount Vernon, WA 98273, USA Appl Microbiol Biotechnol DOI 10.1007/s00253-014-5711-x