How to run SPARQL queries in R (WBG Topical Taxonomy) without parallelization

Question

I am an R user and I am interested to use the World Bank Group (WBG) Topical Taxonomy through SPARQL queries. This can be done directly on the API https://vocabulary.worldbank.org/PoolParty/sparql/taxonomy but it can be done also through R by using the functions load.rdf (to load the taxonomy.rdf rdfxml file downloaded from https://vocabulary.worldbank.org/ ) and after using the sparql.rdf to perform the query. These functions are available on the "rrdf" package

These are the three lines of codes:

taxonomy_file <- load.rdf("taxonomy.rdf")

query <- "SELECT DISTINCT ?nodeOnPath WHERE {http://vocabulary.worldbank.org/taxonomy/435 http://www.w3.org/2004/02/skos/core#narrower* ?nodeOnPath}"

result_query_1 <- sparql.rdf(taxonomy_file,query)

What I obtain from result_query_1 is exactly the same I get through the API.

However, the load.rdf function uses all the cores available on my computer and not only one. This function is somehow parallelizing the load task over all the core available on my machine and I do not want that. I haven't found any option on that function to specify its serialized usege. Therefore, I am trying to find other solutions. For instance, I have tried "rdf_parse" and "rdf_query" of the package "rdflib" but without any encouraging result. These are the code lines I have used.

taxonomy_file <- rdf_parse("taxonomy.rdf")

query <- "SELECT DISTINCT ?nodeOnPath WHERE {http://vocabulary.worldbank.org/taxonomy/435 http://www.w3.org/2004/02/skos/core#narrower* ?nodeOnPath}"

result_query_2 <- rdf_query(taxonomy_file , query = query)

Is there any other function that perform this task? The objective of my work is to run several queries simultaneously using foreach.

Thank you very much for any suggestion you could provide me.