Enhancer returns Error 500 when requested format cannot be serialized

The following request:

$ curl -H "Accept: text/tutle" -H "Content-Type: text/plain" -d "Apache Stanbol's intended use is to extend traditional content management systems with semantic services. Other feasible use cases include: direct usage from web applications (e.g. for tag extraction/suggestion; or text completion in search fields), 'smart' content workflows or email routing based on extracted entities, topics, etc." http://localhost:8080/enhancer

notice the typo "tutle" produces the following error:

HTTP ERROR 500

Problem accessing /enhancer. Reason: No serializer available for text/tutle

Caused by: org.apache.clerezza.rdf.core.serializedform.UnsupportedSerializationFormatException: No serializer available for text/tutle
at org.apache.clerezza.rdf.core.serializedform.Serializer.serialize(Serializer.java:142)
at org.apache.stanbol.enhancer.jersey.writers.ContentItemWriter.writeTo(ContentItemWriter.java:167)
at org.apache.stanbol.enhancer.jersey.writers.ContentItemWriter.writeTo(ContentItemWriter.java:82)
at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:306)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1448)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1360)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1350)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:538)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:716)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.apache.felix.http.base.internal.handler.ServletHandler.doHandle(ServletHandler.java:96)
at org.apache.felix.http.base.internal.handler.ServletHandler.handle(ServletHandler.java:79)
at org.apache.felix.http.base.internal.dispatch.ServletPipeline.handle(ServletPipeline.java:42)
at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:49)
at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
at org.apache.stanbol.commons.httpqueryheaders.impl.QueryHeadersFilter.doFilter(QueryHeadersFilter.java:75)
at org.apache.felix.http.base.internal.handler.FilterHandler.doHandle(FilterHandler.java:88)
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:76)
at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:78)
at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
at org.apache.stanbol.commons.web.resources.ResourceServingFilter.doFilterHttp(ResourceServingFilter.java:148)
at org.apache.stanbol.commons.web.resources.ResourceServingFilter.doFilter(ResourceServingFilter.java:91)
at org.apache.felix.http.base.internal.handler.FilterHandler.doHandle(FilterHandler.java:88)
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:76)
at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
at org.apache.stanbol.commons.security.auth.AuthenticatingFilter$1.run(AuthenticatingFilter.java:163)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:536)
at org.apache.stanbol.commons.security.auth.AuthenticatingFilter.doFilter(AuthenticatingFilter.java:159)
at org.apache.felix.http.base.internal.handler.FilterHandler.doHandle(FilterHandler.java:88)
at org.apache.felix.http.base.internal.handler.FilterHandler.handle(FilterHandler.java:76)
at org.apache.felix.http.base.internal.dispatch.InvocationFilterChain.doFilter(InvocationFilterChain.java:47)
at org.apache.felix.http.base.internal.dispatch.HttpFilterChain.doFilter(HttpFilterChain.java:33)
at org.apache.felix.http.base.internal.dispatch.FilterPipeline.dispatch(FilterPipeline.java:48)
at org.apache.felix.http.base.internal.dispatch.Dispatcher.dispatch(Dispatcher.java:39)
at org.apache.felix.http.base.internal.DispatcherServlet.service(DispatcherServlet.java:67)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:943)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)