JEFFERSON CITY, Mo. -- Democrat Jay Nixon proclaimed "a new day" for a state facing historic economic challenges as he was sworn in Monday as Missouri's 55th governor.

On a cold overcast day, Nixon acknowledged that a similar gloom pervades households across the state, as the economic downturn has created concern about an uncertain future.

"The challenges we face are historic. But so are the opportunities," Nixon said to applause as he accented his inaugural remarks with finger jabs. "Ladies and gentlemen: Today marks a new day for Missouri."

Nixon, 52, took the oath of office about five minutes before the noon start of his term prescribed in Missouri law. With one had raised, he placed the other on the crumbling black leather cover of a Bible passed down through his family since the late 1700s. It was held by his two sons, Jeremiah and Will, with his wife, Georgeanne, by his side.

Nixon, who served the past 16 years as attorney general, succeeds Republican Matt Blunt, who chose not to seek a second term as governor.

Missouri's new governor takes over with the state facing a projected $342 million budget shortfall and its unemployment rate hovering around its highest mark since 1991. More than 200,000 Missourians lacked jobs and were looking for them as 2008 drew to a close.

Nixon wants to enact various job creation incentives by the legislature's break in mid-March. He already has support from Republican leaders in the House and Senate.

"We'll turn this economy around by making Missouri a magnet for next-generation jobs," Nixon said. "We'll invest in new technology. We'll inspire cutting-edge innovation. And we'll embrace science, not fear it."

Nixon pledged "a new tone in Jefferson City" and a bipartisan approach to governing.

Republican leaders expressed the same desire.

"We're going to try to work together. Times warrant it, demand it," House Speaker Ron Richard, R-Joplin, said after Nixon's speech.

A native of rural De Soto in eastern Missouri, Nixon comes from a family of public officials. His late mother served on the local school board and city park board, while his father worked as mayor and a municipal judge.

Although people call him Jay, he technically is Jeremiah Nixon the 11th. His family traces its American lineage to the late 1600s. One of his ancestors was the Philadelphia sheriff in 1776, who by some accounts was the first to read the Declaration of Independence to the public after the Continental Congress adopted it.

Nixon worked briefly as an attorney in his home county before winning an open state Senate seat in 1986. He won election as attorney general in 1992 and has failed twice in bids for the U.S. Senate.

A former saxophone player at De Soto High School, Nixon chose his alma mater's marching band to lead the traditional inaugural parade Monday morning. Although Nixon had said he would walk, he road in a red Ford Mustang convertible -- a change that a spokesman said was made because of a forecast for rain.

It did not rain on Nixon's parade, though it was cold, with the temperature around the freezing mark and occasionally gusting winds.

Joining Nixon in the parade -- and in taking their oaths of office Monday -- were new Democratic Attorney General Chris Koster, new Democratic Treasurer Clint Zweifel, returning Democratic Secretary of State Robin Carnahan and returning Republican Lt. Gov. Peter Kinder.

Later Monday, Nixon hosted what he described as a potluck dinner for the public. His campaign ordered 1,000 hamburgers, 250 pounds each of potato salad and baked beans, 125 pounds of salad and 20 gallons of ice tea. Members of the public were encouraged to bring store-bought deserts; homemade cookies and pies were banned because of health officials' concerns about food-borne sicknesses.

The inaugural festivities were to be capped by an evening ball inside the Capitol. The new governor and first lady planned to follow tradition by dancing to "The Missouri Waltz."

Nixon said his inaugural festivities will cost well less than the $250,000 spent by Blunt -- certainly nowhere near the $1 million bash thrown by Holden in 2001. As in the recent past, businesses are picking up most of the tab through contributions to Nixon's campaign fund.