mjhjmtu

My requirement is to print some portion of input in one font( can also be of different size,bold,bg etc) & remaining with another. Is it possible?

Yes, it is possible with escape sequences in the text which must be activated with command line option -e or --escapes.

Have a look at the "SPECIAL ESCAPES" section in the man page (man enscript).

SPECIAL ESCAPES
 Enscript supports special escape sequences which can be used to add some page formatting commands to ASCII
 documents. As a default, special escapes interpretation is off, so all ASCII files print out as everyone
 expects. Special escapes interpretation is activated by giving option -e, --escapes to enscript.

 All special escapes start with the escape character. The default escape character is ^@ (octal 000); escape
 character can be changed with option -e, --escapes. Escape character is followed by escape's name and
 optional options and arguments.

 Currently enscript supports following escapes:

 bgcolor change the text background color. The syntax of the escape is:

 ^@bgcolorred green blue

 where the color components red, green, and blue are given as decimal numbers between values 0 and 1.

 bggray change the text background color. The syntax of the escape is:

 ^@bggraygray

 where gray is the new text background gray value. The default value is 1.0 (white).

 color change the text color. The syntax of the escape is:

 ^@colorred green blue

 where color components red, green and blue are given as decimal numbers between values 0 and 1.

and further down it says:

 font select current font. The syntax of the escape is:

 ^@fontfontname[:encoding]

 where fontname is a standard font specification. Special font specification default can be used to
 select the default body font (enscript's default or the one specified by the command line option -f,
 --font).

 The optional argument encoding specifies the encoding that should be used for the new font. Currently
 the encoding can only be the enscript's global input encoding or ps.

Edit:

An example:

me@debian:~$ echo "normal text @color1 0 0red text @fontCourier-Bold10Courier-Bold 10pt @fontHelvetica-BoldOblique12Helvetica-BoldOblique 12pt @fontdefaultdefault font again" > text.txt 
me@debian:~$ enscript -v -e@ text.txt -o text.ps
AFM: scanning path...
AFM: reading font map "/usr/share/enscript/afm/font.map"
processing file "text.txt"...
[ 1 page * 1 copy ] left in text.ps

Have a look at the font names defined your font.map file. Take a font name and add the size (in pt) to it.