It's a reasonable question (see Gankutsuou: The Count of Monte Cristo), but I think the answer is no. Note that I also have not read either work, but from looking at the Wikipedia articles for the manga Emma by Kaoru Mori and the novel Emma by Jane Austen:
- The manga Emma is set in 1895 in the Victorian Era. This is much later than the novel Emma, which was published during the Regency Era in 1815.
- One of the defining features of the title character in Jane Austen's novel is that, unlike the heroines of earlier Austen work, she is independently wealthy and runs her own household. The anime's Emma is a commoner, kidnapped as a child for a brothel, who escaped to the streets and was taken in and brought up as a maid by a wealthy family. She is a diligent and hard worker, whereas Austen's Emma was described by Austen as "a heroine whom no one but myself will much like" and is said on the Wikipedia article to have "a strong sense of class".
- Anime's Emma lives in London, whereas Jane Austen's Emma lives in a small country estate in Surrey.
It is possible that the manga's author, Kaoru Mori, incorporated some influence from Austen's work, since she's a self-declared Anglophile,
The author and illustrator of the manga, Kaoru Mori, is a self-professed Anglophile, [...]
(Overview - 2nd sentence)
But overall, it doesn't look like a direct adaptation of Jane Austen's Emma.