The credit crisis brought more trouble to Georgia’s natural gas market this week, this time targeting a marketer that specializes in serving Georgia’s most vulnerable consumers.

Two-year-old Catalyst Energy is about to lose a line of credit needed to stay in business.

Catalyst’s sales niche includes immigrants and those with bad or no credit.

The loss of its own credit appears to be part of a chain reaction that began two weeks ago, when Lehman Brothers collapsed and sent ripples through the financial markets.

The company did not return requests for comment Monday and Tuesday, but the Georgia Public Service Commission has scheduled an emergency meeting for Wednesday to consider whether to move toward an enforcement action. State law requires marketers to have adequate credit or other financial guarantees to pay for the gas it orders.

If Catalyst can’t replace the credit fast or find a suitable buyer, the PSC may have to step in and transfer its customers to another marketer or marketers.

PSC Chairman Chuck Eaton emphasized Tuesday that customers won’t lose gas service.

“Our No. 1 priority is to make sure that service continues, regardless,” he said.

But if customers are either bought by or assigned to new marketers, he said, “if that customer is not happy, that customer can switch.”

As other marketers have done, Catalyst could also find a buyer for its business and customers.

Its customer base, though, is unusual.

Catalyst sells to customers who are often either underserved or unwanted by other marketers.

The company pioneered a pre-paid gas plan, for instance, that gave credit-challenged customers an economical alternative to the state’s “regulated provider” plan, which is always the costliest plan available.

Catalyst also offers customer service in a range of languages.

Catalyst’s problems mark the second time in the past two weeks that the Lehman collapse touched Georgia’s gas market.

Last week, a company that buys gas for Georgia municipal gas providers lost a $709 million, 30-year gas supply contract with Lehman, forcing it to look for new sources for about 5 percent of its gas for this year.

News of the marketer’s troubles surfaced over the weekend, after Catalyst’s lender, Baltimore-based Constellation Energy, informed the marketer that it was cancelling its credit line. The size of the credit line has not been made public.

It remains unclear whether its finances were in trouble aside from the credit issue.

But its lender clearly had problems of its own.

Constellation is the nation’s largest wholesale power marketer and energy trader. Its stock cratered after Lehman Brother’s filed for bankruptcy, because Constellation and Lehman were trading partners.

Within a week of Lehman’s collapse, Constellation announced that it was selling itself to a division of Warren Buffett’s Berkshire Hathaway for $26.50 per share.

Constellation stock had traded at $65.98 just a few weeks earlier. It closed at $24.30 on Tuesday.