Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Improving polyhydroxyalkanoates production in phototrophic mixed
  cultures by optimizing accumulator reactor operating conditions
19
The categories of this paper are: eess
3
The categories of this paper are: physics
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int